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Variant interpretation report

TTR c.238A>G, p.Thr80Ala

NM_000371.4:c.238A>G NP_000362.1:p.(Thr80Ala) Missense · exon 3 View identifiers
Classification
Likely pathogenic

Variant description:

The TTR NM_000371.4:c.238A>G (NP_000362.1:p.(Thr80Ala)) missense variant has not previously been reported in somatic cancers (COSMIC). Experimental evidence: Recombinant A60 TTR showed 86.2% thyroxine binding and 100% aggregation at pH 4.8, but clinical carrier testing found no significant binding change. Based on available guidelines, this variant is considered to be Likely Pathogenic.

Five-step scale from benign to pathogenic. This variant is likely pathogenic. Select a step to read what it means.

Likely pathogenic.A likely pathogenic classification under the recorded framework.

In plain language

Gene-level background from the recorded interpretation.

About TTR

TTR encodes transthyretin, a protein that transports thyroid hormones in the blood and cerebrospinal fluid and helps carry vitamin A. Abnormal transthyretin can form amyloid deposits, causing inherited conditions that may affect the peripheral nerves, heart, eyes, brain coverings, or other tissues. TTR is not known to have a direct cancer association.

LYFE Sciences is an AI system, and it can make mistakes. Criteria may be applied incorrectly, sources may be misread, and a confident-looking classification can still be wrong. Double-check every criterion and its underlying evidence before relying on any call.
01The reasoning

How it was classified

The recorded framework is Generic ACMG/AMP 2015 with ClinGen SVI recommendations. The criteria and strengths shown below come from the saved assessment; this page does not recalculate the classification.

Recorded applied criteria

The applied criteria and their strengths are shown as assessed under the stated framework.

Pathogenic evidence criteria: 5 Benign evidence criteria: 0
Pathogenic criteria applied · 5
PS1Strong
PS1 · strong

Met: the exact TTR p.Thr80Ala change is established as pathogenic in ClinVar and reported independently as the mature-protein T60A/A60 variant.

PS3Supporting
PS3 · supporting

Met at supporting strength: recombinant A60 TTR showed 86.2% thyroxine binding and 100% aggregation at pH 4.8, but clinical carrier testing found no significant binding change.

PM2Supporting
PM2 · supporting

Met at supporting strength: gnomAD v4.1 AF is 1.6728e-05, below the PM2 threshold of 0.0001, with 0 homozygotes.

PP1Supporting
PP1 · supporting

Met at supporting strength: the variant is reported in an affected patient and affected brother within a familial amyloidosis kindred, supporting cosegregation in multiple affected relatives.

PP3Supporting
PP3 · supporting

Met: REVEL 0.675 exceeds the generic PP3 supporting threshold of >=0.644 for missense variants.

Benign criteria applied · 0

No benign criterion marked as applied in the recorded assessment.

Recorded classification: Likely pathogenic

Likely Pathogenic: PS1 strong plus PS3, PM2, PP1, and PP3 supporting satisfy the generic ACMG/AMP combination of one Strong and four Supporting criteria.

02The sources

Evidence at a glance

Evidence summaries and captured source records, where available. Missing entries should not be interpreted as negative findings.

gnomAD v4.1
gnomAD v2.1
Population frequency
27 / 1,614,060 alleles

gnomAD v4.1: 27 / 1,614,060 alleles. Recorded AF 1.6728e-05. Recorded homozygote count 0.

gnomAD v2.1

This variant is present in gnomAD v2.1 (AF= 3.97706e-06; MAF= 0.00040%, 1/251442 alleles, homozygotes = 0) and has highest observed frequency in the European (non-Finnish) population (AF= 8.79214e-06; MAF= 0.00088%, 1/113738 alleles, homozygotes = 0).

gnomAD-Canada

Not available in gnomAD-Canada v1.0.

No screenshot for this evidence
REVEL score
0.675 recorded score

Recorded REVEL score: 0.675. Refer to the recorded PP3/BP4 rationale for interpretation.

ClinVar submissions
16 reported laboratory submissions

14 Pathogenic · 1 Likely pathogenic · 1 pathogenic. ClinVar API review status: criteria provided, multiple submitters, no conflicts.

Context only ClinVar ↗
No screenshot for this evidence
Functional evidence
Not recorded

No standalone functional evidence summary is recorded in evidence_summary.functional.

COSMIC
Cancer Hotspots
Somatic evidence
No matching record reported

This variant has not previously been reported in somatic cancers (COSMIC).

Cancer Hotspots

This variant does not lie in a statistically significant hotspot.

For specialists

Technical detail

ACMG/AMP criteria under Generic ACMG/AMP 2015 with ClinGen SVI recommendations, with the data and sources behind each one.

28 criteria with recorded statuses: 5 met · 8 not met · 10 not assessed · 5 not applicable. Open any row for the full reasoning, the rule and the evidence behind it.

Met Not met Not assessed Not applicable

PS1 is met because the exact p.Thr80Ala protein change is established as pathogenic; the mature-protein notation T60A/A60 refers to the same substitution after accounting for the 20-residue signal peptide.

PM1, PM5, and PP2 remain not assessed because the supplied evidence lacks the required authoritative domain/hotspot, alternate same-residue pathogenic comparator, and gene-level benign-missense constraint evidence, respectively.

BP1 is not met because the supplied TTR evidence supports a missense amyloidogenic mechanism rather than primarily truncating disease causation.

Segregation evidence supports PP1 at supporting strength based on reports of the relevant TTR alanine-for-threonine variant in multiple affected relatives; no case-specific de novo or affected-relative non-segregation evidence is documented for PS2, PM6, or BS4.

Variant-specific biochemical evidence supports altered TTR behavior relevant to amyloid disease, but mixed assay results and lack of clinical diagnostic validation limit PS3 to supporting strength.

No well-established evidence demonstrates absence of damaging effect, so BS3 is not met.

No VCEP covers TTR in this case; generic ACMG/AMP 2015 rules govern.

PS4 is not met because affected-case observations are not accompanied by a matched control comparison sufficient to calculate or demonstrate OR/RR >5.0 with a confidence interval excluding 1.0.

PP4 and BP5 are not assessed because the case-level phenotype/family history and alternate molecular diagnosis information are absent.

PP5 and BP6 are not applied because the exact-variant ClinVar audit shows zero expert-panel submissions, and ordinary submissions or independently available publications do not satisfy the requested triggers.

PM3 is not applicable because the relevant TTR disorder is autosomal dominant rather than recessive.

BP2 is not assessed because the case lacks a second pathogenic variant and phase information establishing cis or trans configuration.

This is a missense variant; PP3/BP4 were adjudicated exclusively with REVEL under the generic missense path.

PP3 is met at supporting strength because REVEL 0.675 is >= 0.644; BP4 is not met because REVEL 0.675 is not <= 0.29.

Met · 5

PS1 StrongACMG_2015Met: the exact TTR p.Thr80Ala change is established as pathogenic in ClinVar and reported independently as the mature-protein T60A/A60 variant. Details ▾Hide ▴
Reasoning

The variant is NP_000362.1:p.(Thr80Ala), also reported using mature TTR numbering as p.Thr60Ala/A60. ClinVar variation 13421 identifies NM_000371.4:c.238A>G (p.Thr80Ala) as Pathogenic with multiple submitters and no conflicts. Independent extracted reports describe the same TTR A60/T60A substitution in affected hereditary amyloidosis cohorts and recombinant-protein assays; the 20-residue signal-peptide numbering difference reconciles T60A/A60 with precursor-protein p.Thr80Ala. SpliceAI max delta is 0.00, so there is no supplied indication that this is being adjudicated as a splice-impacting change rather than the same protein change.

Rule
Same amino acid change as a previously established pathogenic variant regardless of nucleotide change.
Evidence considered
  • ClinVar variation 13421: NM_000371.4(TTR):c.238A>G (p.Thr80Ala), Pathogenic, criteria provided, multiple submitters, no conflicts.
  • Schwarzman et al. 2004, Table 1, Characterization of recombinant TTR variants: A60 is listed under familial amyloid cardiomyopathy; A60 corresponds to precursor-protein p.Thr80Ala after the 20-residue signal-peptide offset.
  • Berk et al. 2013, Results, Patient Characteristics, paragraph 2: T60A is explicitly listed among non-V30M ATTR genotypes; mature T60A corresponds to precursor-protein p.Thr80Ala.
  • SpliceAI result: max delta score 0.00.
Sources
PS3 SupportingACMG_2015Met at supporting strength: recombinant A60 TTR showed 86.2% thyroxine binding and 100% aggregation at pH 4.8, but clinical carrier testing found no significant binding change. Details ▾Hide ▴
Reasoning

PS3 is met at supporting strength. Two variant-specific biochemical studies evaluated the mature TTR A60 substitution, equivalent to NP_000362.1:p.(T80A). Schwarzman et al. used recombinant human TTR, wild-type comparison, and three independent experiments; A60 showed reduced thyroxine binding (86.2 ± 5.45% of wild type), amyloid-beta aggregation inhibition of 26.7 ± 3.38% relative to no-TTR control, and complete TTR aggregation at pH 4.8, supporting altered protein behavior relevant to amyloid disease. Hammarström et al. studied five Appalachian carriers with DNA-confirmed variant status and a thyroxine-binding assay, but found no significant change in binding affinity, so the evidence is mixed and does not justify moderate or strong PS3 calibration. The studies are biologically relevant and include controls, but they were not demonstrated to be clinically validated, reproducible diagnostic-laboratory assays and the positive findings are model-dependent.

Rule
Well-established in vitro or in vivo functional studies supportive of a damaging effect on the gene or gene product.
Evidence considered
  • Schwarzman et al., Table 1, A60 row: recombinant TTR showed relative thyroxine binding of 86.2 ± 5.45% versus wild type, amyloid-beta aggregation of 26.7 ± 3.38% relative to the no-TTR control, and TTR aggregation of 100% at pH 4.8 with no detected aggregation at pH 6.2 or pH 6.8; results were means of three separate experiments ± SD.
  • Hammarström et al., Results/Table 1: five Appalachian-type FAP subjects with DNA-confirmed carrier status had mean thyroxine-binding Ka of 1.08 ± 0.11 × 10^7 M^-1, slightly but not significantly lower than normal; only one of five had amyloidosis symptoms.
  • The functional evidence is variant-specific and biologically relevant but internally mixed, with one recombinant assay showing altered amyloid-related behavior and one carrier study showing no significant thyroxine-binding defect; supporting strength is therefore used rather than moderate or strong.
Still missing
  • No evidence of a clinically validated, reproducible diagnostic-laboratory functional assay was identified.
  • The positive aggregation result was observed at acidic pH and requires human review for disease-mechanism calibration.
  • The historical biochemical report PMID:3722385 was not independently auditable because its text file was unavailable and its extracted record was not present in paper_extracts.json.
Sources
PM2 SupportingACMGMet at supporting strength: gnomAD v4.1 AF is 1.6728e-05, below the PM2 threshold of 0.0001, with 0 homozygotes. Details ▾Hide ▴
Reasoning

PM2 is met at supporting strength. The generic SVI threshold supplied for this case is <=0.0001. The variant is present at very low frequency in gnomAD v4.1 (AF=1.6728e-05; 27/1614060 alleles; 0 homozygotes), with grpmax FAF=1.107e-05, and in gnomAD v2.1 non-cancer exomes at AF=4.22112e-06 (1/236904 alleles; 0 homozygotes). These values are below 0.0001, although the variant is not literally absent from controls.

Rule
Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes or Exome Aggregation Consortium.
Evidence considered
  • gnomAD v4.1 all-comers: AF=1.6728e-05 (27/1614060 alleles), 0 homozygotes, and grpmax FAF=1.107e-05.
  • gnomAD v2.1 non-cancer exomes: AF=4.22112e-06 (1/236904 alleles), 0 homozygotes; the v3.1 non-cancer genome dataset reports AF=1.35188e-05 (2/147942 alleles), 0 homozygotes, and grpmax FAF=4.88e-06.
  • The supplied generic SVI PM2 threshold is <=0.0001; the observed frequencies are below this threshold, so PM2 is supporting rather than absent-from-controls PM2.
Sources
PP1 SupportingACMG_2015Met at supporting strength: the variant is reported in an affected patient and affected brother within a familial amyloidosis kindred, supporting cosegregation in multiple affected relatives. Details ▾Hide ▴
Reasoning

The available family reports concern the exact TTR alanine-for-threonine variant corresponding to p.Thr80Ala under precursor-protein numbering. The literature describes familial amyloidotic polyneuropathy in a large kindred, including an affected patient and affected brother, and another report describes affected members with asymptomatic gene-carrying offspring. This supports cosegregation of the variant with the dominantly inherited phenotype in multiple affected relatives. The evidence does not provide a complete pedigree, a quantified meiosis count, or sufficiently detailed segregation data to justify a stronger level.

Rule
Co-segregation with disease in multiple affected family members in a gene definitively known to cause the disease. ... May be used as stronger evidence with increasing segregation data.
Evidence considered
  • Familial amyloid polyneuropathy: alanine-for-threonine substitution in the transthyretin (prealbumin) molecule (PMID:2122246) reports the exact alanine-for-threonine substitution at mature TTR position 60, corresponding to precursor-protein p.Thr80Ala, in a family with affected patients and asymptomatic gene-carrying offspring.
  • Biochemical and molecular genetic characterization of a new variant prealbumin associated with hereditary amyloidosis (PMID:3722385) describes an affected patient and affected brother from a large Appalachian kindred with the relevant TTR alanine-for-threonine variant.
  • The reports support familial cosegregation but do not provide a complete pedigree or enough quantified informative meioses for a stronger PP1 level.
Still missing
  • Complete pedigree and individual-level genotype/phenotype table
  • Exact number of informative meioses
  • Age and clinical status of all tested relatives
  • Independent confirmation of segregation across additional informative relatives
Sources
PP3 SupportingACMGMet: REVEL 0.675 exceeds the generic PP3 supporting threshold of >=0.644 for missense variants. Details ▾Hide ▴
Reasoning

The variant is a missense substitution, NM_000371.4:c.238A>G (NP_000362.1:p.(Thr80Ala)); therefore the applicable generic PP3/BP4 path is REVEL only. REVEL is 0.675, meeting the published generic PP3 supporting threshold of >= 0.644 from the ClinGen SVI REVEL calibration (Pejaver et al. 2022, PMID:36413997). SpliceAI and BayesDel were not used for PP3 because SpliceAI is the path for intronic, synonymous, or splice-region variants, and no generic BayesDel strength calibration is established.

Rule
Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc.). ... Missense variant -> REVEL only.
Evidence considered
  • NM_000371.4:c.238A>G is a missense variant encoding NP_000362.1:p.(Thr80Ala), so the missense REVEL path applies.
  • Local REVEL lookup reports score 0.675 for this variant.
  • The published generic PP3 supporting threshold is >= 0.644: ClinGen SVI REVEL calibration, Pejaver et al. 2022, Am J Hum Genet, PMID:36413997.
  • SpliceAI max delta 0.00 and BayesDel 0.355953 were not counted because the governing generic rule selects REVEL only for missense variants, and no generic BayesDel strength calibration is established.
Sources
revel

Not met · 8 · evaluated, threshold not reached

PS4 ACMG_2015Not met: affected-case reports lack a matched control comparison, so the required OR/RR >5.0 with a confidence interval excluding 1.0 cannot be established. Details ▾Hide ▴
Reasoning

Generic ACMG/AMP PS4 requires a significant increase in affected individuals compared with controls, with OR/RR >5.0 and a confidence interval excluding 1.0. The verified literature extracts document the exact TTR p.(Thr80Ala)/mature T60A variant in affected hereditary amyloidosis cohorts or families, including 11.5% of non-V30M genotypes in a 130-patient ATTR-FAP trial (PMID:24368466), but they do not provide a matched unaffected-control comparison for this exact variant. gnomAD v4.1 reports 27/1,614,060 alleles (AF 1.6728e-05) in the general population, but no affected-case frequency from the same ascertainment frame is available, so an OR and 95% CI cannot be computed. The PS4-indexed literature_pass leads (PMIDs 1626556, 20301532, 2840822, 35802134, and 4079954) were not present as fetched full-text or paper-extract records; the available literature_pass ai_classified_papers contained no paper classified as PS4. Therefore, case observations and population frequency do not establish the required case-control enrichment.

Rule
The prevalence of the variant in affected individuals is significantly increased compared to the prevalence in controls. ... Relative risk (RR) or odds ratio (OR), as obtained from case-control studies, is >5.0 and the confidence interval around the estimate of RR or OR does not include 1.0.
Evidence considered
  • PMID:24368466, Results, Patient Characteristics: T60A accounted for 11.5% of non-V30M ATTR genotypes in an international randomized trial of 130 patients; the paper did not report a matched control prevalence or a variant-specific affected-versus-control comparison.
  • PMID:3097057, Results/Table 1: five Appalachian-type FAP subjects were studied, including one symptomatic subject and four presymptomatic carriers; this is a family observation, not a case-control comparison.
  • PMID:15185492, Table 1: recombinant A60/T60A functional measurements were reported, but no affected-case or unaffected-control prevalence data were provided.
  • gnomAD v4.1: 27/1,614,060 alleles, AF 1.6728e-05; this population frequency alone cannot supply the affected-case frequency needed for an OR and 95% CI.
Still missing
  • A verified study reporting exact-variant counts in affected cases and matched unaffected or population controls is unavailable.
  • Because matched case and control counts are unavailable, an OR and 95% CI cannot be calculated.
Sources
PP5 ACMG_2015Not met: ClinVar has no exact-variant expert-panel classification, and the supporting publications are available for independent evaluation rather than unavailable evidence. Details ▾Hide ▴
Reasoning

Generic ACMG/AMP PP5 requires a reputable source to recently report the variant as pathogenic when the evidence is not available to the laboratory for independent evaluation. The exact variant is reported as pathogenic in ordinary ClinVar laboratory/literature submissions, but ClinVar records no expert-panel submission (0 expert-panel submissions), and the relevant publications and extracts are available for independent review. The verified literature supports that TTR T60A/T80A is associated with hereditary amyloidosis, including the affected-patient and affected-brother observations in PMID:3722385, but that is independently inspectable evidence rather than an otherwise unavailable reputable-source assertion. Under the requested rule, PP5 is not applied.

Rule
Reputable source recently reports variant as pathogenic, but the evidence is not available to the laboratory to perform an independent evaluation.
Evidence considered
  • ClinVar exact-variant audit for NM_000371.4:c.238A>G (p.Thr80Ala): 20 submissions, 0 expert-panel submissions; observed pathogenic/likely pathogenic assertions are ordinary laboratory or non-expert submissions and cannot trigger PP5 under the requested rule.
  • PMID:3722385 abstract: biochemical studies were conducted on amyloid from one patient and plasma prealbumin from his affected brother in a large Appalachian kindred; this exact-variant evidence is available for independent evaluation.
  • PMID:21992998 and PMID:26017327 were literature_pass candidate reports of TTR T60A in affected hereditary amyloidosis cohorts, but they are not expert-panel ClinVar classifications and therefore do not satisfy the requested PP5 trigger.
Sources
BA1 ACMGNot met: gnomAD v4.1 grpmax FAF is 1.107e-05, below the generic BA1 threshold of 0.05, and the 0.000112022 popmax estimate is not used. Details ▾Hide ▴
Reasoning

BA1 is not met. The governing generic threshold is >=0.05, and the appropriate gnomAD filtering frequency is the grpmax FAF rather than the popmax point estimate. gnomAD v4.1 reports grpmax FAF=1.107e-05, far below 0.05; the highest observed subgroup point estimate, 0.000112022 (7/62488 alleles), is not used for BA1. The variant is also reported as pathogenic in ClinVar, so there is no basis to override the frequency result with a stand-alone benign call.

Rule
Allele frequency is above 5% in Exome Sequencing Project, 1000 Genomes or Exome Aggregation Consortium.
Evidence considered
  • gnomAD v4.1 all-comers: total AF=1.6728e-05 (27/1,614,060 alleles; 0 homozygotes); grpmax FAF=1.107e-05.
  • The highest observed subgroup point estimate is 0.000112022 in Remaining individuals (7/62488 alleles), but the governing guidance requires the filtering grpmax FAF and a population with at least 2000 observed alleles; this subgroup has 62488 observed alleles.
  • ClinVar reports the variant as Pathogenic with criteria provided, multiple submitters, no conflicts; this supports caution against a stand-alone benign call when frequency is not near the BA1 threshold.
Sources
BS1 ACMGNot met: gnomAD v4.1 grpmax FAF is 1.107e-05, far below the generic BS1 default of 0.01, with no frequency evidence suggesting excess prevalence. Details ▾Hide ▴
Reasoning

BS1 is not met on the available population evidence. The generic default is >=0.01, while gnomAD v4.1 grpmax FAF=1.107e-05, well below 0.01; the non-cancer datasets are also below this threshold (v2.1 non-cancer exomes AF=4.22112e-06; v3.1 non-cancer genomes grpmax FAF=4.88e-06). TTR familial amyloid polyneuropathy is described as autosomal dominant and late-onset, so the default 1% threshold is not independently sufficient to establish BS1 without a maximum-credible-frequency calculation, but the observed filtering frequencies are already orders of magnitude below it.

Rule
Allele frequency is greater than expected for the disorder.
Evidence considered
  • gnomAD v4.1 all-comers: grpmax FAF=1.107e-05, compared with the generic BS1 default threshold of 0.01 supplied for this case.
  • The available non-cancer subsets are similarly rare: gnomAD v2.1 non-cancer exomes AF=4.22112e-06 (1/236904 alleles) and gnomAD v3.1 non-cancer genomes grpmax FAF=4.88e-06.
  • PMID:3722385 describes familial amyloidotic polyneuropathy as an autosomal dominant late-onset disorder; therefore a default 1% cutoff should not be treated as a universal maximum credible frequency without disorder-specific prevalence, penetrance, and allelic-heterogeneity inputs.
Sources
BS3 ACMG_2015Not met: one assay found no significant binding change, but recombinant TTR showed 86.2% binding and 100% aggregation at pH 4.8. Details ▾Hide ▴
Reasoning

BS3 is not met. The available variant-specific studies do not establish that TTR p.(T80A) has no damaging effect on protein function or splicing. One study found no significant change in thyroxine-binding affinity, but another controlled recombinant assay found reduced thyroxine binding and complete aggregation at pH 4.8, and the clinical study did not evaluate the full amyloidogenic function of TTR. Therefore, the negative thyroxine-binding result cannot support a well-established benign functional conclusion.

Rule
Well-established in vitro or in vivo functional studies show no damaging effect on protein function or splicing.
Evidence considered
  • Hammarström et al., Table 1: the Appalachian A60 variant had no statistically significant reduction in thyroxine-binding affinity, but this assay addressed binding only and did not establish normal overall TTR function or absence of amyloidogenic activity.
  • Schwarzman et al., Table 1: A60 showed reduced relative thyroxine binding of 86.2 ± 5.45% and 100% TTR aggregation at pH 4.8 in a controlled recombinant assay, which is incompatible with a well-established no-damaging-effect conclusion.
Sources
BP1 ACMG_2015Not met: available TTR disease evidence centers on recurrent pathogenic missense substitutions and amyloidogenic protein behavior, not primarily truncating variants. Details ▾Hide ▴
Reasoning

BP1 is not supported for TTR. The supplied TTR literature describes hereditary amyloidosis as involving numerous disease-associated missense substitutions and reports missense genotypes such as T60A/A60 in affected cohorts and functional assays. It does not show that TTR disease is caused primarily by truncating variants; the available mechanism evidence instead centers on altered TTR protein stability, secretion, aggregation, and amyloid deposition.

Rule
Missense variant in a gene for which primarily truncating variants are known to cause disease.
Evidence considered
  • Schwarzman et al. 2004, Table 1 and experimental context: recombinant TTR missense variants were evaluated for thyroxine binding and aggregation, including A60/T80A.
  • Berk et al. 2013, Results, Patient Characteristics, paragraph 2: multiple missense ATTR genotypes, including T60A, were reported in affected patients.
  • The extracted evidence does not identify primarily truncating TTR variants as the known disease mechanism.
Sources
BP4 ACMGNot met: REVEL 0.675 is above the generic BP4 supporting cutoff of <=0.29 for missense variants. Details ▾Hide ▴
Reasoning

The variant is a missense substitution, so BP4 must be judged on the REVEL path only. REVEL is 0.675, which is above the generic BP4 supporting cutoff of <= 0.29 and therefore does not support a benign/no-impact computational conclusion. The SpliceAI max delta of 0.00 is not used because splice prediction is not the applicable path for a missense variant; BayesDel is not available for generic ACMG strength assignment.

Rule
Multiple lines of computational evidence suggest no impact on gene or gene product (conservation, evolutionary, splicing impact, etc) ... Missense variant -> REVEL only.
Evidence considered
  • NM_000371.4:c.238A>G is a missense variant encoding NP_000362.1:p.(Thr80Ala), so the missense REVEL path applies.
  • Local REVEL lookup reports score 0.675 for this variant.
  • The published generic BP4 supporting threshold is <= 0.29: ClinGen SVI REVEL calibration, Pejaver et al. 2022, Am J Hum Genet, PMID:36413997.
  • SpliceAI max delta 0.00 was not substituted for REVEL because the governing generic rule assigns SpliceAI to intronic, synonymous, or splice-region variants, not missense variants.
Sources
revel
BP6 ACMG_2015Not met: no exact-variant ClinVar expert-panel benign classification exists, and the available literature is not an unavailable benign-source assertion. Details ▾Hide ▴
Reasoning

Generic ACMG/AMP BP6 requires a reputable source to recently report the variant as benign when the evidence is not available to the laboratory for independent evaluation. The exact-variant ClinVar audit shows no expert-panel submissions and no benign or likely-benign expert-panel classification; the available literature instead reports TTR T60A/T80A in hereditary amyloidosis and is independently inspectable. Ordinary submissions, aggregate labels, and non-expert assertions cannot trigger BP6 under the requested rule, so BP6 is not applied.

Rule
Reputable source recently reports variant as benign, but the evidence is not available to the laboratory to perform an independent evaluation.
Evidence considered
  • ClinVar exact-variant audit for NM_000371.4:c.238A>G (p.Thr80Ala): 0 expert-panel submissions and no benign or likely-benign expert-panel classification.
  • PMID:3722385 and PMID:24368466 report the variant in hereditary amyloidosis/ATTR-FAP contexts rather than as a reputable-source benign assertion, and both are available for independent evaluation.
Sources

Not assessed · 10 · no assessment recorded

PS2 ACMG_2015Not assessed: no documented maternity and paternity confirmation, parental variant-negative testing, and absence of family history for a de novo proband. Details ▾Hide ▴
Reasoning

No case-specific proband-parent trio data are documented. In particular, there is no documented confirmation of both maternity and paternity, no parental genotypes demonstrating absence of the variant, and no explicit statement that the proband had no family history. The available literature describes familial TTR amyloidosis, not a confirmed de novo occurrence in this case.

Rule
De novo (both maternity and paternity confirmed) in a patient with the disease and no family history.
Still missing
  • Proband phenotype and family-history documentation
  • Maternal and paternal identity confirmation
  • Maternal and paternal variant testing
  • Evidence that both parents were unaffected or that the proband had no family history
PM1 ACMG_2015Not assessed: no authoritative TTR hotspot or critical-domain annotation with supporting absence of benign variation was supplied for residue 80. Details ▾Hide ▴
Reasoning

The supplied evidence shows no statistically significant hotspot and no COSMIC report, but generic PM1 requires a mutational hotspot or a critical, well-established functional domain without benign variation. No authoritative TTR domain annotation, hotspot definition, or gene-level benign-variation assessment is supplied, so PM1 cannot be adjudicated reliably.

Rule
Located in a mutational hot spot and/or critical and well-established functional domain (e.g. active site of an enzyme) without benign variation.
Evidence considered
  • Cancer Hotspots result: this variant does not lie in a statistically significant hotspot.
  • COSMIC result: this variant has not previously been reported in somatic cancers; this is not a substitute for a germline critical-domain assessment.
  • vcep_materials.json contains no TTR domain table because no VCEP covers TTR.
Still missing
  • Authoritative TTR critical-domain or hotspot annotation covering residue 80.
  • Evidence that the relevant domain or hotspot lacks benign variation.
Sources
PM5 ACMG_2015Not assessed: no different pathogenic missense change at TTR residue 80 (mature residue 60) was confirmed in the supplied evidence. Details ▾Hide ▴
Reasoning

The variant is a missense change at precursor-protein residue 80 (mature TTR residue 60), but the supplied candidate file contains no same-residue comparator variants and explicitly reports that classic PM5 candidate harvesting was not completed. The available extracted papers document the same T60A/A60 variant, not a different missense substitution at that residue, so a pathogenic alternate missense comparator cannot be confirmed.

Rule
Novel missense change at an amino acid residue where a different missense change determined to be pathogenic has been seen before.
Evidence considered
  • pm5_candidates.json: zero same-residue candidates were collected and classic PM5 semantics were not confirmed by the harvesting artifact.
  • The extracted TTR literature reports T60A/A60 itself, which is the same protein change after mature-versus-precursor numbering reconciliation, not a different missense substitution at residue 60/80.
Still missing
  • A comprehensive same-residue search for a different missense TTR variant with an independently established pathogenic classification.
Sources
PM6 ACMG_2015Not assessed: no documented assumed de novo occurrence or parental testing for NM_000371.4:c.238A>G in the proband. Details ▾Hide ▴
Reasoning

No case-specific evidence establishes that NM_000371.4:c.238A>G arose de novo. The available records do not document an affected proband with both parents tested negative, nor do they document an assumed de novo event with the required parental-testing context. Familial reports of TTR p.Thr80Ala do not establish PM6 for this case.

Rule
Assumed de novo, but without confirmation of paternity and maternity.
Still missing
  • Case-specific proband and parental genotypes
  • Documentation supporting a de novo assumption
  • Parental identity and phenotype information
PP2 ACMG_2015Not assessed: TTR missense disease mechanism is supported, but no defined gene-level measure shows a low rate of benign missense variation. Details ▾Hide ▴
Reasoning

The extracted literature supports that disease-associated TTR variation commonly involves missense substitutions and amyloidogenic protein behavior, but the supplied case evidence does not establish the required low rate of benign missense variation for TTR under a defined gene-level metric or threshold. Because both parts of PP2 must be supported, the criterion is not assessed.

Rule
Missense variant in a gene that has a low rate of benign missense variation and where missense variants are a common mechanism of disease.
Evidence considered
  • Schwarzman et al. 2004, Table 1: multiple TTR amino-acid variants were experimentally characterized, including A60, which was listed under familial amyloid cardiomyopathy.
  • Berk et al. 2013, Results, Patient Characteristics, paragraph 2: the hereditary ATTR trial reports multiple missense genotypes, including T60A, among affected patients.
  • No supplied source provides a gene-level benign-missense rate or a governing threshold for deciding that TTR has a low rate of benign missense variation.
Still missing
  • A gene-level benign-missense constraint or equivalent metric for TTR with an applicable threshold.
  • A documented assessment that missense variants are a common disease mechanism for the relevant TTR disorder.
Sources
PP4 ACMG_2015Not assessed: the patient's phenotype and family history are not provided, so phenotype specificity for a single-gene disease cannot be judged. Details ▾Hide ▴
Reasoning

The generic PP4 rule requires the patient's phenotype or family history to be highly specific for a disease with a single genetic etiology. The supplied case evidence identifies the variant and its literature associations but does not provide the present patient's phenotype, family history, diagnostic findings, or a documented phenotype-specific differential. The criterion therefore cannot be assessed without case-level clinical information.

Rule
Patient’s phenotype or family history is highly specific for a disease with a single genetic etiology.
Still missing
  • Current-patient phenotype, diagnostic findings, and family history are required.
  • The specific disease phenotype being evaluated and whether it has a single genetic etiology are not documented.
BS2 ACMG_2015Not assessed: gnomAD has 0 homozygotes, but its unphenotyped carriers cannot establish healthy adulthood for this autosomal-dominant late-onset disorder. Details ▾Hide ▴
Reasoning

BS2 is not assessed. gnomAD shows no homozygotes (v2.1, v2.1 non-cancer, v3.1 non-cancer, and v4.1), but the available population records do not establish that any heterozygous carrier was a healthy adult at an age sufficient to exclude a late-onset TTR phenotype. The governing BS2 definition requires observation in a healthy adult and full penetrance expected at an early age; the relevant TTR disease is described as autosomal dominant late-onset, so unphenotyped gnomAD carriers cannot satisfy BS2.

Rule
Observed in a healthy adult individual for a recessive (homozygous), dominant (heterozygous), or X-linked (hemizygous) disorder, with full penetrance expected at an early age.
Evidence considered
  • gnomAD v2.1: 1/251442 alleles and 0 homozygotes; gnomAD v4.1: 27/1614060 alleles and 0 homozygotes; the non-cancer v2.1 and v3.1 datasets also report 0 homozygotes.
  • The gnomAD records provide allele counts and homozygote counts but do not document age, clinical phenotype, or healthy-adult status for individual carriers.
  • PMID:3722385 describes familial amyloidotic polyneuropathy as an autosomal dominant late-onset disorder, making absence of phenotype data especially important for BS2.
Still missing
  • No age- and phenotype-confirmed healthy adult carrier observations were provided.
Sources
BS4 ACMG_2015Not assessed: no affected family members are documented as variant-negative, so lack of segregation cannot be established. Details ▾Hide ▴
Reasoning

The available evidence does not document affected relatives who lack the variant. Reports of asymptomatic carriers are not, by themselves, lack of segregation in affected family members, particularly for this late-onset disorder. Therefore the BS4 requirement is not established, and the phenocopy caveat cannot be meaningfully evaluated from the available family data.

Rule
Lack of segregation in affected members of a family.
Evidence considered
  • The available family reports mention affected relatives and asymptomatic carriers, but do not document an affected family member who lacks the variant.
Still missing
  • Genotypes and phenotypes for all affected relatives
  • Documentation of any affected variant-negative relatives
  • Assessment of late-onset penetrance and phenocopy risk
Sources
BP2 ACMG_2015Not assessed: no second pathogenic variant or parental/offspring phase data establish cis or trans configuration for BP2. Details ▾Hide ▴
Reasoning

BP2 requires observation of this variant in trans with a pathogenic variant for a fully penetrant dominant gene/disorder, or in cis with a pathogenic variant in any inheritance pattern. The case evidence contains no second pathogenic variant and no parental, offspring, or other phase information establishing either trans or cis configuration. The TTR disorder is described as autosomal dominant, but inheritance mode alone cannot establish BP2 without the required allelic observation and phase.

Rule
BP2: Observed in trans with a pathogenic variant for a fully penetrant dominant gene/disorder or observed in cis with a pathogenic variant in any inheritance pattern.
Evidence considered
  • The consolidated case evidence provides no report of a second pathogenic variant in the tested individual and no parental, offspring, or other molecular phase result.
  • The available TTR literature describes the relevant disorder as autosomal dominant, but does not provide the cis/trans observation required for BP2 in this case.
Still missing
  • A second pathogenic variant and definitive phase information are needed to determine whether the variant is in trans or cis under BP2.
Sources
BP5 ACMG_2015Not assessed: no case is documented with both this variant and a confirmed alternate molecular basis for the disease. Details ▾Hide ▴
Reasoning

The generic BP5 rule requires the variant to be found in a case with an alternate molecular basis for disease. The supplied evidence documents hereditary TTR amyloidosis observations but does not identify a particular case with a confirmed alternate pathogenic molecular cause of the disease. Absence of that case-level information prevents assessment rather than permitting BP5 to be applied.

Rule
Variant found in a case with an alternate molecular basis for disease.
Still missing
  • A case-level report showing a confirmed alternate molecular diagnosis in the same affected individual is required.
Not applicable · 5· recorded as not applicable Show reasons ▾Hide reasons ▴
PVS1 N/ANot applicable: PVS1 requires a null variant (nonsense, frameshift, canonical splice, start-loss or stop-loss), and this is a missense variant. Details ▾Hide ▴
Reasoning

PVS1 (ClinGen SVI PVS1 recommendations, PMC6185798, pvs1_generic_framework) applies only to null variant classes — nonsense, frameshift, canonical ±1/2 splice-consensus, translation-initiation-codon loss, and stop-loss variants — each expected to trigger nonsense-mediated decay or otherwise abolish normal protein function. NM_000371.4:c.238A>G in TTR is a missense substitution predicted to produce NP_000362.1:p.(Thr80Ala). As a result, no null-variant mechanism (nonsense-mediated decay, truncation, or canonical splice disruption) is triggered by this variant class, so PVS1's structural prerequisite is not met by this variant class. No VCEP criteria specification covers PVS1 for TTR, so the generic ACMG/AMP 2015 definition applies. This determination was made deterministically from the variant's consequence class, prior to LLM adjudication.

Rule
deterministic_prefilter: requires_null_variant_class
Evidence considered
  • Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
  • VCEP criterion policy: absent
Sources
pvs1_generic_framework ↗generic_acmg_combination_rules
PM3 N/ANot applicable: PM3 is limited to recessive disorders, whereas TTR hereditary amyloidosis is described as autosomal dominant. Details ▾Hide ▴
Reasoning

PM3 is restricted to recessive disorders and requires the tested variant to be detected in trans with a pathogenic variant. The available case evidence identifies TTR hereditary amyloidosis as an autosomal dominant disorder, so the recessive-disorder applicability condition for PM3 is not met; no PM3 evidence is assessed.

Rule
PM3: For recessive disorders, detected in trans with a pathogenic variant
Evidence considered
  • Biochemical and molecular genetic characterization of a new variant prealbumin associated with hereditary amyloidosis (PMID:3722385) describes familial amyloidotic polyneuropathy as an autosomal dominant late-onset disorder; this establishes that the relevant TTR disorder is not recessive for PM3 applicability.
Sources
PM4 N/ANot applicable: PM4 requires a protein-length change, and this is a missense variant. Details ▾Hide ▴
Reasoning

PM4 (Richards et al. 2015, PMID:25741868) applies to protein length changes: in-frame insertions/deletions in a non-repetitive region, or stop-loss variants that extend the protein past the reference stop codon. NM_000371.4:c.238A>G in TTR is a missense substitution predicted to produce NP_000362.1:p.(Thr80Ala). As a result, no change in protein length occurs, so there is nothing for this criterion to evaluate, so PM4's structural prerequisite is not met by this variant class. No VCEP criteria specification covers PM4 for TTR, so the generic ACMG/AMP 2015 definition applies. This determination was made deterministically from the variant's consequence class, prior to LLM adjudication.

Rule
deterministic_prefilter: requires_stop_loss_or_nonrepeat_indel
Evidence considered
  • Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
  • VCEP criterion policy: absent
Sources
pvs1_generic_framework ↗generic_acmg_combination_rules
BP3 N/ANot applicable: BP3 requires an in-frame indel in a repeat region, and this is a missense variant. Details ▾Hide ▴
Reasoning

BP3 (Richards et al. 2015, PMID:25741868) applies to in-frame insertions/deletions located in a repetitive region without a known function. NM_000371.4:c.238A>G in TTR is a missense substitution predicted to produce NP_000362.1:p.(Thr80Ala). As a result, the variant does not alter protein length within a repeat region, so there is nothing for this criterion to evaluate, so BP3's structural prerequisite is not met by this variant class. No VCEP criteria specification covers BP3 for TTR, so the generic ACMG/AMP 2015 definition applies. This determination was made deterministically from the variant's consequence class, prior to LLM adjudication.

Rule
deterministic_prefilter: requires_repeat_region_indel
Evidence considered
  • Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
  • VCEP criterion policy: absent
Sources
pvs1_generic_framework ↗generic_acmg_combination_rules
BP7 N/ANot applicable: BP7 requires a synonymous variant, and this is a missense variant. Details ▾Hide ▴
Reasoning

BP7 (Richards et al. 2015, PMID:25741868) is defined for a synonymous (silent) variant for which splicing prediction algorithms predict no impact to the splice consensus sequence and the nucleotide is not highly conserved. NM_000371.4:c.238A>G in TTR is a missense substitution predicted to produce NP_000362.1:p.(Thr80Ala). As a result, the encoded protein sequence is altered, so the criterion's silent-variant premise does not hold regardless of any splicing prediction, so BP7's structural prerequisite is not met by this variant class. No VCEP criteria specification covers BP7 for TTR, so the generic ACMG/AMP 2015 definition applies. This determination was made deterministically from the variant's consequence class, prior to LLM adjudication.

Rule
deterministic_prefilter: requires_synonymous
Evidence considered
  • Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
  • VCEP criterion policy: absent
Sources
generic_acmg_combination_rules

Identifiers

Gene
TTR
Transcript
NM_000371.4
Coding (HGVS c.)
NM_000371.4:c.238A>G
Protein (HGVS p.)
NP_000362.1:p.(Thr80Ala)
GRCh38
chr18:31595157 A>G
GRCh37
chr18:29175120 A>G
Location and type
Exon 3 · missense
ClinVar
13421, 577420

Gene diagram

Every interpreted variant in TTR, mapped onto the exon structure of NM_000371.4. Select a row to find it on the plot.

TTRNM_000371.4
Fetching transcript structure from UCSC…
gnomAD v4.1 27 / 1,614,060 alleles AF 1.67e-05 · 0 homozygotes · FAF 1.11e-05
gnomAD v2.1 1 / 251,442 alleles AF 3.98e-06 · 0 homozygotes
gnomAD-Canada v1.0 Allele count data not recorded

By genetic ancestry

gnomAD v4.1

AF 1.7e-05 · 27 / 1,614,060 alleles · 0 hom · FAF 1.1e-05
Remaining individuals7 / 62,488 0.00011
European (non-Finnish)20 / 1,180,032 1.7e-05
0 alternate alleles recorded in 8 other groups: Admixed American, European (Finnish), Amish, East Asian, Middle Eastern, South Asian, Ashkenazi Jewish, African/African American.

gnomAD v2.1

AF 4e-06 · 1 / 251,442 alleles · 0 hom
European (non-Finnish)1 / 113,738 8.8e-06
0 alternate alleles recorded in 7 other groups: African/African American, Admixed American, Ashkenazi Jewish, East Asian, European (Finnish), Remaining individuals, South Asian.

Statements

gnomAD v4.1

This variant is present in gnomAD v4.1 (AF= 1.6728e-05; MAF= 0.00167%, 27/1614060 alleles, homozygotes = 0) and has highest observed frequency in the Remaining individuals population (AF= 0.000112022; MAF= 0.01120%, 7/62488 alleles, homozygotes = 0); grpmax FAF= 1.107e-05.

gnomAD v2.1

This variant is present in gnomAD v2.1 (AF= 3.97706e-06; MAF= 0.00040%, 1/251442 alleles, homozygotes = 0) and has highest observed frequency in the European (non-Finnish) population (AF= 8.79214e-06; MAF= 0.00088%, 1/113738 alleles, homozygotes = 0).

gnomAD-Canada

Not available in gnomAD-Canada v1.0.

SpliceAI and Pangolin

SpliceAI acceptor lossat -54 bp
0.000
SpliceAI acceptor gainat -28 bp
0.000
SpliceAI donor lossat -30 bp
0.000
SpliceAI donor gainat +204 bp
0.000
Pangolin splice lossmagnitude shown
-0.002
Pangolin splice gain
0.003

Other predictors

REVEL
0.675
BayesDel
0.356

How the predictions were used

PP3 SupportingACMGMet: REVEL 0.675 exceeds the generic PP3 supporting threshold of >=0.644 for missense variants. Details ▾Hide ▴
Reasoning

The variant is a missense substitution, NM_000371.4:c.238A>G (NP_000362.1:p.(Thr80Ala)); therefore the applicable generic PP3/BP4 path is REVEL only. REVEL is 0.675, meeting the published generic PP3 supporting threshold of >= 0.644 from the ClinGen SVI REVEL calibration (Pejaver et al. 2022, PMID:36413997). SpliceAI and BayesDel were not used for PP3 because SpliceAI is the path for intronic, synonymous, or splice-region variants, and no generic BayesDel strength calibration is established.

Rule
Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc.). ... Missense variant -> REVEL only.
Evidence considered
  • NM_000371.4:c.238A>G is a missense variant encoding NP_000362.1:p.(Thr80Ala), so the missense REVEL path applies.
  • Local REVEL lookup reports score 0.675 for this variant.
  • The published generic PP3 supporting threshold is >= 0.644: ClinGen SVI REVEL calibration, Pejaver et al. 2022, Am J Hum Genet, PMID:36413997.
  • SpliceAI max delta 0.00 and BayesDel 0.355953 were not counted because the governing generic rule selects REVEL only for missense variants, and no generic BayesDel strength calibration is established.
Sources
revel
BP4 ACMGNot met: REVEL 0.675 is above the generic BP4 supporting cutoff of <=0.29 for missense variants. Details ▾Hide ▴
Reasoning

The variant is a missense substitution, so BP4 must be judged on the REVEL path only. REVEL is 0.675, which is above the generic BP4 supporting cutoff of <= 0.29 and therefore does not support a benign/no-impact computational conclusion. The SpliceAI max delta of 0.00 is not used because splice prediction is not the applicable path for a missense variant; BayesDel is not available for generic ACMG strength assignment.

Rule
Multiple lines of computational evidence suggest no impact on gene or gene product (conservation, evolutionary, splicing impact, etc) ... Missense variant -> REVEL only.
Evidence considered
  • NM_000371.4:c.238A>G is a missense variant encoding NP_000362.1:p.(Thr80Ala), so the missense REVEL path applies.
  • Local REVEL lookup reports score 0.675 for this variant.
  • The published generic BP4 supporting threshold is <= 0.29: ClinGen SVI REVEL calibration, Pejaver et al. 2022, Am J Hum Genet, PMID:36413997.
  • SpliceAI max delta 0.00 was not substituted for REVEL because the governing generic rule assigns SpliceAI to intronic, synonymous, or splice-region variants, not missense variants.
Sources
revel
BP7 N/ANot applicable: BP7 requires a synonymous variant, and this is a missense variant. Details ▾Hide ▴
Reasoning

BP7 (Richards et al. 2015, PMID:25741868) is defined for a synonymous (silent) variant for which splicing prediction algorithms predict no impact to the splice consensus sequence and the nucleotide is not highly conserved. NM_000371.4:c.238A>G in TTR is a missense substitution predicted to produce NP_000362.1:p.(Thr80Ala). As a result, the encoded protein sequence is altered, so the criterion's silent-variant premise does not hold regardless of any splicing prediction, so BP7's structural prerequisite is not met by this variant class. No VCEP criteria specification covers BP7 for TTR, so the generic ACMG/AMP 2015 definition applies. This determination was made deterministically from the variant's consequence class, prior to LLM adjudication.

Rule
deterministic_prefilter: requires_synonymous
Evidence considered
  • Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
  • VCEP criterion policy: absent
Sources
generic_acmg_combination_rules

Statement

In silico

SpliceAI predicts no significant splice impact for this variant (max delta score = 0.00). REVEL score = 0.675. BayesDel score = 0.355953.

10 paper records listed. 5 cited in the classification.

Cited in the classification

  • Amyloidogenic and anti-amyloidogenic properties of recombinant transthyretin variants.
    Schwarzman AL et al. · 2004 Mar
    The study explicitly describes TTR A60, corresponding to precursor-protein p.Thr80Ala with the 20-residue signal-peptide offset, and evaluates it in recombinant TTR assays. A60 showed relative thyroxine binding of 86.2 +/- 5.45%, amyloid-beta aggregation of 26.7 +/- 3.38% relative to control, and complete TTR aggregation at pH 4.8; it was listed under familial amyloid cardiomyopathy.
    → PS1 · strong → PS3 · supporting Names this variant
    PMID 15185492 ↗
    Source detail
    A60 FAC 86.2 + 5.45 26.7 + 3.38 100 ND ND

    Location Table 1, Characterization of recombinant TTR variants

    Context Recombinant human TTR variants expressed in E. coli, purified, and assessed for thyroxine binding, amyloid-beta aggregation inhibition, and TTR aggregation at pH 4.8, 6.2, and 6.8; results were means of three experiments +/- SD.

  • Familial amyloid polyneuropathy: alanine-for-threonine substitution in the transthyretin (prealbumin) molecule.
    The paper reports an alanine-for-threonine substitution at mature TTR position 60 in a familial amyloid polyneuropathy kindred, with affected patients and asymptomatic gene-carrying offspring; this corresponds to precursor-protein p.Thr80Ala.
    → PP1 · supporting Names this variant
    PMID 2122246 ↗
    Source detail
    A previously reported family with amyloid polyneuropathy (FAP) was reinvestigated to determine the type of mutation in the transthyretin (prealbumin) molecule. Transthyretin was isolated from amyloid-laden myocardium and serum, and tryptic peptides were resolved by high-performance liquid chromatography. Amino acid sequencing of an anomalous peptide revealed an alanine-for-threonine substitution corresponding to position No. 60 of the transthyretin monomer.

    Location PubMed abstract; family and variant description

    Context Familial amyloid polyneuropathy kindred; biochemical characterization of transthyretin from amyloid and serum, with carrier detection by hybrid isoelectric focusing.

  • Repurposing diflunisal for familial amyloid polyneuropathy: a randomized clinical trial.
    The study explicitly lists TTR T60A, corresponding to precursor-protein p.Thr80Ala, among non-V30M ATTR genotypes; T60A accounted for 11.5% of those genotypes. It does not provide variant-specific functional or segregation results for T60A.
    → PS1 · strong Names this variant
    PMID 24368466 ↗
    Source detail
    Non-V30M ATTR included T60A (11.5%), L58H (11.5%), F64L (3.1%), S50R (3.1%), and 17 other genotypes (eTable 2).

    Location Results, Patient Characteristics, paragraph 2

    Context International randomized, double-blind, placebo-controlled diflunisal trial in 130 patients with ATTR-FAP recruited from eight amyloid centers in five countries; T60A was reported among non-V30M genotypes.

  • Reduced affinity for thyroxine in two of three structural thyroxine-binding prealbumin variants associated with familial amyloidotic polyneuropathy.
    The paper describes five subjects from an Appalachian TTR p.Thr80Ala-type kindred; one had amyloidosis symptoms and four were presymptomatic gene carriers. This provides family context but does not document affected variant-negative relatives.
    → PS3 · supporting Names this variant
    PMID 3097057 ↗
    Source detail
    a recently discovered kindred from the Appalachian area of the United States has an alanine substitution for threonine at position 60 of TBPA (16).

    Location Introduction/Comments, page 1433; Results, page 1434; Table 1

    Context Five individuals from an Appalachian familial amyloid polyneuropathy kindred; carrier status established by DNA restriction-fragment analysis and thyroxine-binding measured in vitro.

  • Biochemical and molecular genetic characterization of a new variant prealbumin associated with hereditary amyloidosis.
    The paper describes familial amyloidotic polyneuropathy as an autosomal dominant late-onset disorder and reports biochemical and molecular characterization of the relevant TTR alanine-for-threonine variant in an affected patient and affected brother from a large Appalachian kindred.
    → PP1 · supporting Names this variant
    PMID 3722385 ↗
    Source detail
    Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant late-onset disorder characterized by the extracellular deposition of amyloid fibrils. Biochemical studies were conducted on amyloid from one patient and plasma prealbumin from his affected brother, both part of a large kindred from the Appalachian region of the United States.

    Location PubMed abstract; study subjects and kindred description

    Context Affected members of a large Appalachian familial amyloidotic polyneuropathy kindred; biochemical and molecular characterization of amyloid and plasma transthyretin.

Other recorded publications

  • The biological and chemical basis for tissue-selective amyloid disease.
    No paper-specific finding is recorded.
    PMID 15820680 ↗
  • Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology.
    No paper-specific finding is recorded.
    PMID 25741868 ↗
  • Identification of carriers of a variant plasma prealbumin (transthyretin) associated with familial amyloidotic polyneuropathy type I.
    No paper-specific finding is recorded.
    PMID 2981253 ↗
  • HRS/EHRA expert consensus statement on the state of genetic testing for the channelopathies and cardiomyopathies: this document was developed as a partnership between the Heart Rhythm Society (HRS) and the European Heart Rhythm Association (EHRA).
    No paper-specific finding is recorded.
    PMID 21810866 ↗
  • 2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: the Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC).
    No paper-specific finding is recorded.
    PMID 25173338 ↗

Screenshots represent source records captured during evidence collection. Select one to view the recorded source content.

All source links

Statements for reports

The evidence statements recorded by the interpretation pipeline. They have not been reinterpreted by the page.

gnomAD v4.1

This variant is present in gnomAD v4.1 (AF= 1.6728e-05; MAF= 0.00167%, 27/1614060 alleles, homozygotes = 0) and has highest observed frequency in the Remaining individuals population (AF= 0.000112022; MAF= 0.01120%, 7/62488 alleles, homozygotes = 0); grpmax FAF= 1.107e-05.

gnomAD v2.1

This variant is present in gnomAD v2.1 (AF= 3.97706e-06; MAF= 0.00040%, 1/251442 alleles, homozygotes = 0) and has highest observed frequency in the European (non-Finnish) population (AF= 8.79214e-06; MAF= 0.00088%, 1/113738 alleles, homozygotes = 0).

gnomAD-Canada

Not available in gnomAD-Canada v1.0.

ClinVar

This variant has been reported in ClinVar as Pathogenic (14 clinical laboratories) and as Likely pathogenic (1 clinical laboratory) and as pathogenic (1 clinical laboratory). (ClinVarID = 13421)

In silico

SpliceAI predicts no significant splice impact for this variant (max delta score = 0.00). REVEL score = 0.675. BayesDel score = 0.355953.

Somatic

This variant does not lie in a statistically significant hotspot. This variant has not previously been reported in somatic cancers (COSMIC).

Cancer Hotspots

This variant does not lie in a statistically significant hotspot.