The RYR1 NM_000540.3:c.1840C>T (NP_000531.2:p.(Arg614Cys)) missense variant has previously been reported in somatic cancers (COSMIC; COSV100616513, n = 1 time). Based on available guidelines, this variant is considered to be a Variant of Uncertain Significance (VUS). This variant is considered to be drug response by the VCEP (ClinPGx; ClinVar ID 12964).
Five-step scale from benign to pathogenic. This variant is uncertain. Select a step to read what it means.
This variantScenario
BenignPathogenic
Uncertain.The recorded classification is uncertain significance.
In plain language
Gene-level background from the recorded interpretation.
Words with a dotted underline have a short definition. Hover or tap them.
About RYR1
RYR1 encodes a calcium-release channel in skeletal muscle that helps connect the sarcoplasmic reticulum with the transverse tubules and regulate muscle contraction. Changes in RYR1 are associated with malignant hyperthermia susceptibility, central core disease, and minicore myopathy with external ophthalmoplegia; it has no established cancer role.
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01The reasoning
How it was classified
The recorded framework is ClinGen RYR1 VCEP v2.0. 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.
Met at moderate strength: REVEL 0.927 exceeds the VCEP's >0.85 threshold for deleterious computational evidence.
PP5Supporting
PP5 · supporting
Not applicable: the RYR1 VCEP states that PP5 is not for use under the ClinGen Sequence Variant Interpretation VCEP Review Committee recommendation.
Benign criteria applied · 0
No benign criterion marked as applied in the recorded assessment.
Recorded classification: Uncertain significance
VUS: PP3 (moderate) plus PP5 (supporting) do not satisfy any ACMG/AMP 2015 pathogenic, likely pathogenic, benign, or likely benign combination rule.
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
118 / 1,614,054 alleles
gnomAD v4.1: 118 / 1,614,054 alleles. Recorded AF 7.31078e-05. Recorded homozygote count 0.
gnomAD v2.1
This variant is present in gnomAD v2.1 (AF= 0.000106059; MAF= 0.01061%, 30/282862 alleles, homozygotes = 0) and has highest observed frequency in the European (non-Finnish) population (AF= 0.000193519; MAF= 0.01935%, 25/129186 alleles, homozygotes = 0); grpmax FAF= 0.00021229.
gnomAD-Canada
This variant is present in gnomAD-Canada v1.0 (AF= 0.0001086484137331595, 2/18408 alleles, homozygotes = 0).
ACMG/AMP criteria under ClinGen RYR1 VCEP v2.0, with the data and sources behind each one.
28 criteria with recorded statuses: 2 met · 6 not met · 8 not assessed · 12 not applicable. Open any row for the full reasoning, the rule and the evidence behind it.
Among the requested codon, residue, and domain criteria, none provides usable positive or negative evidence for this RYR1 p.Arg614Cys variant: PS1 lacks a distinct same-amino-acid nucleotide change, PM1 excludes residue 614, PM5 lacks an alternate residue-614 missense variant, and PP2/BP1 are VCEP-not-applicable.
PS2 and PM6 are not assessed because no qualifying proven or assumed de novo case has sufficient documented parental-origin evidence.
PP1 is not assessed because the available extracted reports do not provide an exact count of qualifying disease-cosegregating meioses.
BS4 is not applicable under the RYR1 VCEP specification.
Only PS4, PP4, PP5, BP5, and BP6 were adjudicated.
PS4 remains not assessed because the available variant-specific evidence does not establish the VCEP-required case-point total or a qualifying odds ratio with 95% confidence interval; PP4, PP5, BP5, and BP6 are explicitly not applicable in the RYR1 VCEP specification.
Population evidence is limited to the four requested criteria: BA1 and BS1 are not met because the VCEP popmax thresholds are not exceeded; BS2 is not assessed because the required healthy-adult negative IVCT/CHCT observation is unavailable; PM2 is not applicable under the VCEP.
All-comers gnomAD totals and population maxima were used because the VCEP text does not specify a non-cancer or exome-only population source for these criteria.
No criteria match.
Met · 2
PP3ModerateVCEPMet at moderate strength: REVEL 0.927 exceeds the VCEP's >0.85 threshold for deleterious computational evidence.
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Reasoning
The variant is a missense SNV, so the VCEP's PP3 missense computational path applies. That path names REVEL and specifies a score greater than 0.85; the case-specific REVEL score is 0.927, which meets the VCEP threshold. No splice predictor or other computational predictor is counted for PP3 because the governing rule names REVEL for this path.
VCEP rule
Multiple lines of computational evidence support a deleterious effect on the gene or gene product ... * Use REVEL score of >0.85
Evidence considered
RYR1 VCEP CSPEC PP3 rule: use REVEL score >0.85; this missense variant has REVEL 0.927.
Local REVEL predictor lookup for NC_000019.9:g.38948185C>T / NM_000540.3:c.1840C>T: REVEL score 0.927.
PP5SupportingVCEPNot applicable: the RYR1 VCEP states that PP5 is not for use under the ClinGen Sequence Variant Interpretation VCEP Review Committee recommendation.
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PS1VCEPNot met: no different nucleotide change producing the same pathogenic p.Arg614Cys amino-acid substitution was identified.
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Reasoning
The variant is RYR1 p.Arg614Cys (c.1840C>T). The available evidence establishes this exact nucleotide change as pathogenic, but does not identify a different nucleotide change producing the same Arg614Cys amino-acid substitution. Therefore the VCEP's same-amino-acid PS1 requirement is not met.
VCEP rule
Same amino acid change as a previously established pathogenic variant regardless of nucleotide change
* Previously established pathogenic variant must reach a classification of pathogenic without PS1
Evidence considered
Case normalization: NM_000540.3:c.1840C>T produces NP_000531.2:p.(Arg614Cys).
ClinVar reports the exact c.1840C>T variant as Pathogenic with an expert-panel review status; this is the assessed variant itself, not a distinct nucleotide change producing the same amino acid change.
Still missing
A previously established pathogenic or likely pathogenic alternate nucleotide change producing p.Arg614Cys is not documented in the available evidence.
PM1VCEPNot met: residue 614 is outside all VCEP-specified PM1 regions, which are 1-552, 2,101-2,458, and 4,631-4,991.
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Reasoning
RYR1 residue 614 is outside every region specified by the VCEP: residues 1-552, 2,101-2,458, and 4,631-4,991. The VCEP materials contain no RYR1 domain-table entry and the VCEP rule does not name an independent hotspot source route. PM1 is therefore not met.
VCEP rule
Located in a mutational hot spot and/or critical and well established functional domain.
* Residues 1-552 (N-terminal region) and 2,101-2,458 (central region)
* PM1 should not be applied at a moderate weight with PS1/PM5, see PM1_Supporting. ... Located in a mutational hot spot and/or critical and well established functional domain.
* Residues 1-552 (N-terminal region) and 2,101-2,458 (central region), if PS1/PM5 applicable then PM1 should be used at supporting
* Residues 4,631-4,991 (C-terminal region).
Evidence considered
The VCEP PM1 moderate region list is residues 1-552 and 2,101-2,458; its supporting region list is residues 1-552, 2,101-2,458, and 4,631-4,991.
The variant is p.Arg614Cys, so the affected residue is 614.
vcep_materials.json has an empty domain_tables object for RYR1.
PM5VCEPNot met: zero qualifying alternate missense variants at RYR1 residue 614 were identified for comparison with p.Arg614Cys.
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Reasoning
The variant is a missense change at residue 614, but the collected same-residue comparator review found zero same-residue candidates and no qualifying pathogenic or likely pathogenic alternate missense variant. The VCEP PM5 requirement is therefore not met.
VCEP rule
Missense change at an amino acid residue where a different missense varaint previously determined to be pathogenic
* Previously established pathogenic variant must reach a classification of pathogenicity without PM5
* Grantham score for alternate pathogenic variant must be less than for variant being assessed ... Missense change at an amino acid residue where a different missense variant previously determined to be pathogenic.
* Previously established likely pathogenic variant can be considered supporting evidence, must reach a classification of likely pathogenic without PM5.
* Grantham score for alternate likely pathogenic variant must be less than for variant being assessed.
Evidence considered
The PM5 candidate assessment reports 5 candidates seen but 0 same-residue candidates, 0 expert-panel pathogenic/likely pathogenic candidates, and 0 non-expert-majority pathogenic/likely pathogenic candidates for residue 614.
BA1VCEPNot met: the highest all-comers gnomAD popmax FAF is 0.00021229, below the VCEP BA1 threshold of >0.0038.
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Reasoning
The RYR1 VCEP specifies BA1 when popmax allele frequency is >0.0038 (0.38%). The highest available all-comers gnomAD population frequency is the gnomAD v2.1 grpmax FAF of 0.00021229 (0.021229%), and gnomAD v4.1 grpmax FAF is 0.00007408 (0.007408%); both are below 0.0038. The VCEP does not specify a non-cancer or exome-only source for BA1, so the all-comers values are used.
BS1VCEPNot met: the highest all-comers gnomAD popmax FAF is 0.00021229, below the VCEP BS1 threshold of >0.0008.
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Reasoning
The RYR1 VCEP specifies BS1 at strong strength when popmax allele frequency is >0.0008 (0.08%). The highest available all-comers gnomAD population frequency is the gnomAD v2.1 grpmax FAF of 0.00021229 (0.021229%), with gnomAD v4.1 grpmax FAF of 0.00007408 (0.007408%); neither exceeds 0.0008. The VCEP does not specify a non-cancer or exome-only source for BS1, so the all-comers values are used.
BP4VCEPNot met: REVEL 0.927 is above, not below, the VCEP's <0.5 threshold for no computational impact.
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Reasoning
The variant is a missense SNV and therefore is within the VCEP's BP4 computational scope. The governing rule names REVEL and requires a score below 0.5 for no computational impact. The case-specific REVEL score is 0.927, so the BP4 threshold is not met. SpliceAI is not counted because the VCEP BP4 rule names REVEL, not SpliceAI, for this situation.
VCEP rule
Computational evidence suggest no impact on gene or gene product, REVEL score of <0.5
Evidence considered
RYR1 VCEP CSPEC BP4 rule: computational evidence suggests no impact when REVEL is <0.5; this missense variant has REVEL 0.927.
Local REVEL predictor lookup for NC_000019.9:g.38948185C>T / NM_000540.3:c.1840C>T: REVEL score 0.927.
PS2VCEPNot assessed: no proven or assumed de novo case with sufficient parental-origin evidence is documented for RYR1 c.1840C>T.
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Reasoning
No qualifying proven or assumed de novo case is documented for RYR1 c.1840C>T. The reviewed family evidence describes inherited R614C transmission, including R614C in a mother and in her children, rather than a proband with documented parental-origin testing. The VCEP point-based PS2 rule therefore cannot be evaluated.
Evidence considered
The variant is RYR1 c.1840C>T (p.Arg614Cys/R614C).
The extracted family report describes R614C in a mother and in her children, including compound-heterozygous offspring, which is inherited transmission rather than a documented de novo observation.
The extracted Swiss cohort report describes R614C in three families and mutation-positive patients assessed by IVCT, but it does not document a qualifying de novo case with parental-origin confirmation.
No reviewed source provides the case-level maternity and paternity evidence or the complete clinical details needed to score PS2.
Still missing
A case-level report documenting the proband's phenotype and confirmed maternity and paternity, or the VCEP-defined evidence for an assumed de novo case, is needed to assign PS2 points.
PS3VCEPNot assessed: one dyspedic-myotube study reports R614C hypersensitivity, but the VCEP requires either ≥3 HEK293 assays with controls, ≥3 independent ex vivo studies, or a knock-in mouse.
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Reasoning
The variant-specific functional evidence is directionally damaging but does not satisfy a defined VCEP calibration path. Yang et al. (PMID:12732639) expressed the corresponding R614C RyR1 construct in RyR-null dyspedic skeletal myotubes and reported significantly increased sensitivity to caffeine and 4-chloro-m-cresol versus WT, with calcium imaging, WT comparison, and replicate experiments. However, this is not the VCEP's specified HEK293 assay, and the available evidence does not document three or more independent ex vivo studies, a knock-in mouse with the required paired findings, or the VCEP-required HEK293 controls and n≥3. The Swiss IVCT study (PMID:11668625) reports stronger contracture effects for R614C but does not establish one of the VCEP's listed PS3 calibration paths. Therefore PS3 is not assessed rather than assigned a strength.
VCEP rule
Well-established functional studies supportive of a damaging effect on protein function
* Increased sensitivity to RYR1 agonist in HEK293 in vitro assay, Ca2+ release significantly increased compared to WT, controls to include known pathogenic and benign variants, n≥3.
* Three or more independent ex vivo studies all showing release of Ca2+ in response to RYR1 agonist
* Knock-in mouse showing MH reaction in response to RYR1 agonist OR increased sensitivity to RYR1 agonists in ex vivo tissue/cells (but not both, which would be PS3_strong)...Well-established functional studies supportive of a damaging effect on protein function
* Two independent ex vivo studies all showing release of Ca2+ in response to RYR1 agonist
Evidence considered
Yang et al. 2003 (PMID:12732639), Functional Defects in Six Ryanodine Receptor Isoform-1 Mutations, Results/Figs. 2-4: human-equivalent R614C was expressed in RyR-null dyspedic 1B5 myotubes; mutant myotubes showed significantly greater sensitivity to KCl depolarization, caffeine, and 4-chloro-m-cresol than WT, with calcium imaging and two experiments performed in triplicate.
Fiege et al. 2002 (PMID:11668625), Results/Table 2 and Discussion: R614C was identified in three Swiss MH families and showed stronger IVCT functional effects than several comparator variants, but the study reports contracture-test results rather than one of the VCEP's explicitly calibrated PS3 assay paths.
Still missing
No qualifying VCEP-defined PS3 path is documented: three or more independent ex vivo calcium-release studies, the specified HEK293 assay with known pathogenic and benign controls and n≥3, or the specified knock-in mouse evidence.
PS4VCEPNot assessed: R614C occurs in 3 of 48 MH families, but no VCEP-required odds ratio and 95% confidence interval are available at popmax FAF 0.00007408.
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Reasoning
The RYR1 VCEP PS4 rule requires either a defined number of MH case points with popmax gnomAD ≤0.00006, or an odds ratio threshold when popmax gnomAD >0.00006. The reviewed variant-specific literature includes a Swiss cohort reporting R614C in 3 of 48 unrelated MH families and 65 MHS plus 9 MHE mutation-positive patients, but it does not provide the VCEP-defined MH case-point total or a case/control allele-count table sufficient to calculate the required odds ratio and 95% CI. The gnomAD v4.1 popmax FAF is 0.00007408, so the >0.00006 odds-ratio route is applicable: 0.00007408 > 0.00006? yes; however, no qualifying OR and 95% CI can be established from the available evidence. The literature-pass PS4 leads were checked against their available abstract records, and the fetched full-text extracts were checked where available; they report family occurrence, segregation, functional data, or general RYR1 findings rather than a qualifying case-control comparison for this variant.
VCEP rule
The prevalence of the variant in affected individuals significantly increased compared with the prevalence in controls.
* ≥7 MH case points. Probands with a personal or family history of an MH event are awarded 0.5 points, probands with a personal or family history of a positive (MHS) IVCT/CHCT are awarded an additional 0.5 points. Probands with multiple variants in RYR1 classified as VUS, likely pathogenic or pathogenic are not considered. Popmax in gnomAD ≤0.00006.
* For variants with popmax MAF gnomAD >0.00006, an odds ratio of ≥18.7 when comparing MH case points to allele count in gnomAD can qualify. Popmax in gnomAD must be <0.0038. ... The prevalence of the variant in affected individuals is significantly increased compared with the prevalence in controls.
* 2-6 MH case points. Probands with a personal or family history of an MH event are awarded 0.5 points, probands with a personal or family history of a positive (MHS) IVCT/CHCT are awarded an additional 0.5 points. Probands with multiple variants in RYR1 classified as VUS, likely pathogenic or pathogenic are not considered. Popmax in gnomAD ≤0.00006.
* For variants with popmax MAF in gnomAD >0.00006, an odds ratio of ≥4.33 when comparing MH case points to allele count in gnomAD can qualify. Popmax in gnomAD must be <0.0038. ... The prevalence of the variant in affected individuals is significantly increased compared withthe prevalence in controls.
* 1 MH case point. Probands with a personal or family history of an MH event are awarded 0.5 points, probands with a personal or family history of a positive (MHS) IVCT/CHCT are awarded an additional 0.5 points. Probands with multiple variants in RYR1 classified as VUS, likely pathogenic or pathogenic are not considered. Popmax in gnomAD ≤0.00006.
For variants with popmax MAF in gnomAD >0.00006, an odds ratio of ≥2.08 when comparing MH case points to allele count in gnomAD can qualify. Popmax in gnomAD must be <0.0038.
Evidence considered
ClinGen RYR1 VCEP PS4 strong rule: the prevalence of the variant in affected individuals must be significantly increased compared with controls; ≥7 MH case points with popmax gnomAD ≤0.00006 can qualify, or for popmax MAF >0.00006 and <0.0038, OR ≥18.7 can qualify.
ClinGen RYR1 VCEP PS4 moderate rule: 2-6 MH case points with popmax gnomAD ≤0.00006 can qualify, or for popmax MAF >0.00006 and <0.0038, OR ≥4.33 can qualify.
ClinGen RYR1 VCEP PS4 supporting rule: 1 MH case point with popmax gnomAD ≤0.00006 can qualify, or for popmax MAF >0.00006 and <0.0038, OR ≥2.08 can qualify.
gnomAD v4.1: RYR1 c.1840C>T has popmax FAF 0.00007408 (7.408e-05), with 118/1,614,054 total alleles and 0 homozygotes; the VCEP comparison is 0.00007408 > 0.00006? yes.
Genotype-phenotype comparison of the Swiss malignant hyperthermia population, PMID:11668625, Results/Mutation frequency and Table 2: R614C was found in 3 of 48 unrelated MH families; the cohort included 74 mutation-positive patients, 65 MHS and 9 MHE by IVCT.
Presence of two different genetic traits in malignant hyperthermia families, PMID:12411788: R614C was observed in several MH families and in carriers assessed by IVCT, including compound-heterozygous and homozygous family members; this is family/segregation evidence, not a VCEP-quantified case-control comparison.
Literature-pass PS4 leads PMID:12937085, PMID:14985404, PMID:24121147, PMID:29635721, PMID:34012068, and PMID:9334205 were checked against their available abstract-level records; no qualifying variant-specific case/control counts, OR, and 95% CI were documented.
Still missing
VCEP-defined MH case-point total for NM_000540.3:c.1840C>T
Matched case/control allele counts or an odds ratio with 95% confidence interval
PM6VCEPNot assessed: no case-level parental testing and clinical documentation establish an assumed de novo event for RYR1 c.1840C>T.
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Reasoning
No qualifying assumed de novo case is documented for RYR1 c.1840C>T. The available evidence contains inherited family observations and no case-level parental testing or clinical documentation sufficient to establish an assumed de novo event. The VCEP point-based PM6 rule therefore cannot be evaluated.
Evidence considered
The available extracted family evidence describes inherited R614C in carrier parents and offspring, not an assumed de novo event.
No reviewed source provides sufficient parental-origin and clinical case details to classify an observation as an assumed de novo case under the VCEP rule.
Still missing
A case-level report with sufficient parental testing and phenotype information is needed to determine whether any observation qualifies as an assumed de novo case and to assign PM6 points.
PP1VCEPNot assessed: available R614C family reports do not provide the exact 3-4 disease-cosegregating meioses required for VCEP Supporting PP1.
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Reasoning
The VCEP specifies PP1 as Supporting for co-segregation in 3-4 reported meioses, Moderate for 5-6, and Strong for at least 7. The reviewed evidence documents R614C in multiple malignant hyperthermia families and genotype-phenotype assessment by IVCT, but the available extracts do not provide an exact count of disease-cosegregating meioses. Therefore, no PP1 strength can be assigned without extrapolating beyond the reported evidence.
Evidence considered
VCEP PP1 thresholds are Supporting for 3-4 reported meioses, Moderate for 5-6 reported meioses, and Strong for at least 7 reported meioses.
The extracted German-family report describes R614C in family members and genotype-phenotype observations, including inherited transmission and IVCT classifications, but does not state a count of qualifying meioses.
The extracted Swiss cohort report states that R614C was found in 3 families and that mutation-positive patients were assessed by IVCT; this is family/cohort context, not an exact reported meiosis count.
Still missing
The original pedigrees and family-level genotype/IVCT results must be reviewed to count qualifying disease-cosegregating meioses without double-counting individuals or families.
BS2VCEPNot assessed: no healthy adult R614C carrier with a negative IVCT/CHCT result is documented, although gnomAD reports zero homozygotes.
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Reasoning
The VCEP requires either two or more variant-positive individuals with a negative IVCT/CHCT test for strong BS2, or one variant-positive individual with a negative IVCT/CHCT test for moderate BS2, in the context of a healthy adult and full penetrance expected at an early age. The available RYR1 Arg614Cys literature documents affected or test-characterized families and an R614C homozygote, but does not document a healthy adult R614C carrier with a negative IVCT/CHCT result. gnomAD reports zero homozygotes, but population homozygote absence does not establish the VCEP's required healthy-adult negative-test evidence.
VCEP 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.
* Two or more variant positive individuals with a negative IVCT/CHCT test ... 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.
* One variant positive individual with a negative IVCT/CHCT test
Evidence considered
ClinGen RYR1 VCEP CSPEC BS2 strong rule requires two or more variant-positive individuals with a negative IVCT/CHCT test; the moderate rule requires one variant-positive individual with a negative IVCT/CHCT test.
Presence of two different genetic traits in malignant hyperthermia families (PMID:12411788), Results, Family Li137 and related family reports: R614C homozygosity and compound heterozygosity were reported in MH families, but the extracted findings do not document a healthy adult R614C carrier with a negative IVCT/CHCT test.
gnomAD v2.1 all-comers: total homozygotes=0; gnomAD v4.1 all-comers: total homozygotes=0. This does not satisfy the VCEP's required healthy-adult negative IVCT/CHCT observation.
Still missing
A documented R614C-positive healthy adult with a negative IVCT/CHCT result, or two such individuals for strong BS2, is required.
BS3VCEPNot assessed: no study documents the VCEP-required absence of calcium release or agonist sensitivity in the specified in-vitro, ex-vivo, or knock-in-mouse conditions.
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Reasoning
No available study provides VCEP-calibrated benign functional evidence for R614C. The available variant-specific functional study instead reports increased agonist sensitivity and abnormal calcium handling, while the IVCT study reports stronger contracture effects. Neither documents no significant calcium release or no increased RYR1-agonist sensitivity under the VCEP's required in-vitro, ex-vivo, or knock-in-mouse conditions. BS3 is therefore not assessed, not assigned a benign strength, and not treated as contradicted evidence because the VCEP rule cannot be evaluated to a qualifying benign endpoint from the available studies.
VCEP rule
Well-established functional studies show no damaging effect on protein function
* Three or more independent ex vivo studies, NO significant release of Ca2+ in response to agonist...Well-established functional studies show no damaging effect on protein function
* No significant increased sensitivity to RYR1 agonist in an approved in vitro assay, Ca2+ release measured, n≥3
* One or two independent ex vivo studies, NO significant release of Ca2+ in response to agonist
* Knock-in mouse showing no MH reaction in response to RYR1 agonist AND no increased sensitivity to RYR1 agonists in ex vivo tissue/cells
Evidence considered
Yang et al. 2003 (PMID:12732639), Results/Figs. 2-4: R614C-expressing dyspedic myotubes had significantly lower agonist thresholds and increased sensitivity to caffeine and 4-chloro-m-cresol compared with WT, which does not provide the VCEP-defined benign endpoint.
Fiege et al. 2002 (PMID:11668625), Results/Table 2: R614C carriers had stronger IVCT functional effects, not absence of contracture or absent agonist sensitivity.
Still missing
No qualifying VCEP-defined BS3 path is documented: an approved in-vitro assay with measured calcium release and n≥3 showing no significant increased sensitivity, one or two qualifying ex vivo studies, or the specified benign knock-in mouse findings.
BP2VCEPNot assessed: the only documented second-variant observation is trans compound heterozygosity, not the VCEP-required cis pathogenic-variant observation.
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Reasoning
The VCEP BP2 rule requires the assessed variant to be observed in cis with a pathogenic variant in any inheritance pattern. The available variant-specific paper reports RYR1 p.Arg614Cys and R2454C in the same probands as compound heterozygous variants inherited from different parents, which is trans rather than cis; it does not establish the assessed variant in cis with a pathogenic variant. Because no qualifying cis observation is documented in the available evidence, BP2 cannot be evaluated as met or not met.
VCEP rule
Observed in cis with a pathogenic variant in any inheritance pattern
Evidence considered
VCEP BP2 rule: observed in cis with a pathogenic variant in any inheritance pattern.
Presence of two different genetic traits in malignant hyperthermia families, Results, Family Li200: the mother carried RYR1 R614C, the father carried R2454C, and proband II-1 and brother II-2 were compound heterozygous for R614C and R2454C, documenting trans inheritance rather than cis.
The cited report does not establish that R2454C is pathogenic under the evidence available for this criterion, and it provides no qualifying cis-phase observation.
Still missing
A documented cis-phase observation between p.Arg614Cys and a pathogenic variant is not available.
Not applicable · 12· recorded as not applicableShow reasons ▾Hide reasons ▴PVS1VCEPNot applicable: the VCEP excludes PVS1 for this gene.
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Reasoning
The ClinGen Malignant Hyperthermia Susceptibility Expert Panel Specifications to the ACMG/AMP Variant Interpretation Guidelines for RYR1 Version 2.0 marks PVS1 as not applicable. The VCEP states: "PVS1 is not applicable. MHS is due to gain of function variants in RYR1." NM_000540.3:c.1840C>T in RYR1 is a missense substitution predicted to produce NP_000531.2:p.(Arg614Cys). This determination was made deterministically from the VCEP criteria specification, prior to LLM adjudication.
VCEP rule
deterministic_prefilter: vcep_not_applicable
Evidence considered
Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
PM3VCEPNot applicable: the VCEP excludes PM3 because malignant hyperthermia susceptibility is autosomal dominant with reduced penetrance.
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Reasoning
The ClinGen Malignant Hyperthermia Susceptibility Expert Panel Specifications to the ACMG/AMP Variant Interpretation Guidelines for RYR1 Version 2.0 expressly exclude PM3 because malignant hyperthermia susceptibility is an autosomal dominant disorder with reduced penetrance. Therefore, the reported homozygous or compound-heterozygous observations for RYR1 p.Arg614Cys do not permit PM3 application under this VCEP framework.
VCEP rule
PM3 is not applicable. MHS is inherited as an autosomal dominant trait with reduced penetrance.
Evidence considered
VCEP PM3 specification: PM3 is not applicable for this VCEP because MHS is inherited as an autosomal dominant trait with reduced penetrance.
The available literature includes homozygous and compound-heterozygous RYR1 p.Arg614Cys observations, but PM3 remains excluded by the VCEP rule regardless of those observations.
PM4VCEPNot applicable: the VCEP excludes PM4 for this gene.
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Reasoning
The ClinGen Malignant Hyperthermia Susceptibility Expert Panel Specifications to the ACMG/AMP Variant Interpretation Guidelines for RYR1 Version 2.0 marks PM4 as not applicable. The VCEP states: "PM4 is not applicable. The majority of RYR1 variants that are causative for MHS are missense variants." NM_000540.3:c.1840C>T in RYR1 is a missense substitution predicted to produce NP_000531.2:p.(Arg614Cys). This determination was made deterministically from the VCEP criteria specification, prior to LLM adjudication.
VCEP rule
deterministic_prefilter: vcep_not_applicable
Evidence considered
Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
PP2VCEPNot applicable: the RYR1 VCEP excludes PP2 because missense constraint is not established, with a gnomAD z-score of 1.92.
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Reasoning
The RYR1 VCEP explicitly marks PP2 as not applicable because RYR1 does not appear constrained for missense variation, citing a gnomAD missense constraint z-score of 1.92.
VCEP rule
PP2 is not applicable. RYR1 does not appear to be constrained for missense variation with a z-score of 1.92 in gnomAD.
Evidence considered
The VCEP instruction states: PP2 is not applicable because RYR1 does not appear to be constrained for missense variation, with a z-score of 1.92 in gnomAD.
PP4VCEPNot applicable: the RYR1 VCEP excludes PP4 because CACNA1S variants also cause malignant hyperthermia susceptibility.
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Reasoning
The RYR1 VCEP explicitly excludes PP4 because CACNA1S variants can also cause malignant hyperthermia susceptibility; no phenotype-specific PP4 evidence can therefore be applied under this VCEP.
VCEP rule
PP4 is not applicable, variants in CACNA1S also result in MHS.
Evidence considered
The VCEP CSPEC entry states: PP4 is not applicable, variants in CACNA1S also result in MHS.
BS4VCEPNot applicable: the RYR1 VCEP excludes BS4 because MHS phenotype determination is not sufficiently reliable for this criterion.
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Reasoning
The RYR1 VCEP explicitly excludes BS4 because MHS phenotype is determined using IVCT or CHCT, IVCT has an approximately 6% false-positive rate, and phenotype cannot be reliably determined in individuals without an MH crisis.
VCEP rule
BS4 is not applicable. Phenotype for MHS is routinely determined based on the vitro contraction test (IVCT) that has a false positive rate of approximately 6% (PP1) or the caffeine-halothane contracture test (CHCT). As the phenotype in individuals who have not experienced an MH crisis cannot be reliably determined BS4 is not utilized.
Evidence considered
The VCEP instruction for BS4 states that BS4 is not applicable because MHS phenotype is routinely determined by IVCT or CHCT, IVCT has an approximately 6% false-positive rate, and phenotype without an MH crisis cannot be reliably determined.
BP3VCEPNot applicable: the VCEP excludes BP3 for this gene.
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Reasoning
The ClinGen Malignant Hyperthermia Susceptibility Expert Panel Specifications to the ACMG/AMP Variant Interpretation Guidelines for RYR1 Version 2.0 marks BP3 as not applicable. The VCEP states: "BP3 is not applicable. RYR1 does not have repetitive regions without known function." NM_000540.3:c.1840C>T in RYR1 is a missense substitution predicted to produce NP_000531.2:p.(Arg614Cys). This determination was made deterministically from the VCEP criteria specification, prior to LLM adjudication.
VCEP rule
deterministic_prefilter: vcep_not_applicable
Evidence considered
Deterministic consequence classification: missense (prefetch.json normalized protein consequence)
BP5VCEPNot applicable: the RYR1 VCEP excludes BP5 because MHS individuals have been described with two pathogenic RYR1 variants.
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Reasoning
The RYR1 VCEP marks BP5 as not applicable because individuals have been described with MHS and two pathogenic RYR1 variants; an alternate molecular basis cannot be used for BP5 in this framework.
VCEP rule
BP5 is not applicable as individuals have been described with MHS and two pathogenic variants in RYR1.
Evidence considered
The VCEP CSPEC BP5 entry states that BP5 is not applicable because individuals have been described with MHS and two pathogenic variants in RYR1.
BP6VCEPNot applicable: the RYR1 VCEP states that BP6 is not for use under the ClinGen Sequence Variant Interpretation VCEP Review Committee recommendation.
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Reasoning
The RYR1 VCEP marks BP6 as not applicable and states that this criterion is not for use as recommended by the ClinGen Sequence Variant Interpretation VCEP Review Committee.
VCEP rule
This criterion is not for use as recommended by the ClinGen Sequence Variant Interpretation VCEP Review Committee.
Evidence considered
The VCEP CSPEC BP6 entry marks the criterion not applicable and prohibits its use.
BP7N/ANot applicable: the variant is missense (p.Arg614Cys), whereas BP7 requires a synonymous (silent) variant.
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Reasoning
BP7 is limited by the VCEP rule to synonymous (silent) variants. NM_000540.3:c.1840C>T is a missense variant producing p.Arg614Cys, so BP7 is outside its own scope and is not evaluated from splice or conservation predictions.
VCEP rule
A synonymous (silent) variant for which splicing prediction algorithms predict no impact to the splice consensus sequence nor the creation of a new splice site AND the nucleotide is not highly conserved
Evidence considered
RYR1 VCEP CSPEC BP7 rule applies to a synonymous (silent) variant; the case variant is annotated as missense, p.Arg614Cys.
AF 7.3e-05 · 118 / 1,614,054 alleles · 0 hom · FAF 7.4e-05
European (Finnish)7 / 63,998
0.00011
Remaining individuals6 / 62,508
9.6e-05
European (non-Finnish)104 / 1,180,012
8.8e-05
African/African American1 / 74,992
1.3e-05
0 alternate alleles recorded in 6 other groups: Admixed American, Amish, East Asian, Middle Eastern, South Asian, Ashkenazi Jewish.
gnomAD v2.1
AF 0.00011 · 30 / 282,862 alleles · 0 hom · FAF 0.00021
European (non-Finnish)25 / 129,186
0.00019
Remaining individuals1 / 7,226
0.00014
European (Finnish)3 / 25,122
0.00012
East Asian1 / 19,952
5e-05
0 alternate alleles recorded in 4 other groups: African/African American, Admixed American, Ashkenazi Jewish, South Asian.
gnomAD-Canada
AF not recorded · ? / ? alleles
Statements
gnomAD v4.1
This variant is present in gnomAD v4.1 (AF= 7.31078e-05; MAF= 0.00731%, 118/1614054 alleles, homozygotes = 0) and has highest observed frequency in the European (Finnish) population (AF= 0.000109378; MAF= 0.01094%, 7/63998 alleles, homozygotes = 0); grpmax FAF= 7.408e-05.
gnomAD v2.1
This variant is present in gnomAD v2.1 (AF= 0.000106059; MAF= 0.01061%, 30/282862 alleles, homozygotes = 0) and has highest observed frequency in the European (non-Finnish) population (AF= 0.000193519; MAF= 0.01935%, 25/129186 alleles, homozygotes = 0); grpmax FAF= 0.00021229.
gnomAD-Canada
This variant is present in gnomAD-Canada v1.0 (AF= 0.0001086484137331595, 2/18408 alleles, homozygotes = 0).
PP3ModerateVCEPMet at moderate strength: REVEL 0.927 exceeds the VCEP's >0.85 threshold for deleterious computational evidence.
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Reasoning
The variant is a missense SNV, so the VCEP's PP3 missense computational path applies. That path names REVEL and specifies a score greater than 0.85; the case-specific REVEL score is 0.927, which meets the VCEP threshold. No splice predictor or other computational predictor is counted for PP3 because the governing rule names REVEL for this path.
VCEP rule
Multiple lines of computational evidence support a deleterious effect on the gene or gene product ... * Use REVEL score of >0.85
Evidence considered
RYR1 VCEP CSPEC PP3 rule: use REVEL score >0.85; this missense variant has REVEL 0.927.
Local REVEL predictor lookup for NC_000019.9:g.38948185C>T / NM_000540.3:c.1840C>T: REVEL score 0.927.
BP4VCEPNot met: REVEL 0.927 is above, not below, the VCEP's <0.5 threshold for no computational impact.
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Reasoning
The variant is a missense SNV and therefore is within the VCEP's BP4 computational scope. The governing rule names REVEL and requires a score below 0.5 for no computational impact. The case-specific REVEL score is 0.927, so the BP4 threshold is not met. SpliceAI is not counted because the VCEP BP4 rule names REVEL, not SpliceAI, for this situation.
VCEP rule
Computational evidence suggest no impact on gene or gene product, REVEL score of <0.5
Evidence considered
RYR1 VCEP CSPEC BP4 rule: computational evidence suggests no impact when REVEL is <0.5; this missense variant has REVEL 0.927.
Local REVEL predictor lookup for NC_000019.9:g.38948185C>T / NM_000540.3:c.1840C>T: REVEL score 0.927.
BP7N/ANot applicable: the variant is missense (p.Arg614Cys), whereas BP7 requires a synonymous (silent) variant.
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Reasoning
BP7 is limited by the VCEP rule to synonymous (silent) variants. NM_000540.3:c.1840C>T is a missense variant producing p.Arg614Cys, so BP7 is outside its own scope and is not evaluated from splice or conservation predictions.
VCEP rule
A synonymous (silent) variant for which splicing prediction algorithms predict no impact to the splice consensus sequence nor the creation of a new splice site AND the nucleotide is not highly conserved
Evidence considered
RYR1 VCEP CSPEC BP7 rule applies to a synonymous (silent) variant; the case variant is annotated as missense, p.Arg614Cys.
Homozygous and heterozygous Arg614Cys mutations (1840C-->T) in the ryanodine receptor gene co-segregate with malignant hyperthermia susceptibility in a German family.
Determination of a positive malignant hyperthermia (MH) disposition without the in vitro contracture test in families carrying the RYR1 Arg614Cys mutation.
Genotype-phenotype comparison of the Swiss malignant hyperthermia population.
The paper explicitly describes RYR1 c.1840C>T as R614C. In a Swiss malignant hyperthermia cohort, R614C was identified in 3 of 48 unrelated families; among 74 mutation-positive patients, 65 were MHS and 9 were MHE by IVCT.
Mutation R614C was found in 3 families (6%) and mutation G2434R in 2 families (4%). Mutation R2458C was present in one family (2%). No homozygous mutation carriers were found.
Presence of two different genetic traits in malignant hyperthermia families: implication for genetic analysis, diagnosis, and incidence of malignant hyperthermia susceptibility.
The paper explicitly describes RYR1 c.1840C>T as R614C. In family Li200, R614C was identified in the mother while the proband and his brother carried R614C together with R2454C. In family Li137, both parents carried R614C, one patient was homozygous, and her children inherited the mutation; carriers were classified by European in vitro contracture testing.
Mutation screening of the RyR1 gene revealed the presence of the “pig” mutation, i.e., the R614C mutation, in his mother’s DNA (patient I-2) and of the R2454C mutation in his father’s DNA, while proband II-1 and his brother (patient II-2) were compound heterozygous bearing both R614C and R2454C mutations (fig. 1).
Results, Family Li200; additional relevant observations in Results, Families Li137 and Li53, and Discussion
Functional defects in six ryanodine receptor isoform-1 (RyR1) mutations associated with malignant hyperthermia and their impact on skeletal excitation-contraction coupling.
The study expressed WT RyR1 and six human MH-associated RyR1 mutants, including R614C, in RyR-null dyspedic skeletal myotubes. R614C myotubes showed heightened sensitivity to KCl depolarization, caffeine, and 4-chloro-m-cresol compared with WT, and the study identified altered calcium and magnesium regulation consistent with an MH-related functional defect.
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= 7.31078e-05; MAF= 0.00731%, 118/1614054 alleles, homozygotes = 0) and has highest observed frequency in the European (Finnish) population (AF= 0.000109378; MAF= 0.01094%, 7/63998 alleles, homozygotes = 0); grpmax FAF= 7.408e-05.
gnomAD v2.1
This variant is present in gnomAD v2.1 (AF= 0.000106059; MAF= 0.01061%, 30/282862 alleles, homozygotes = 0) and has highest observed frequency in the European (non-Finnish) population (AF= 0.000193519; MAF= 0.01935%, 25/129186 alleles, homozygotes = 0); grpmax FAF= 0.00021229.
gnomAD-Canada
This variant is present in gnomAD-Canada v1.0 (AF= 0.0001086484137331595, 2/18408 alleles, homozygotes = 0).
ClinVar
This variant has been reported in ClinVar as Pathogenic (27 clinical laboratories) and as pathogenic (1 clinical laboratory) and as drug response by ClinPGx (expert panel) and as Pathogenic by ClinGen Malignant Hyperthermia Susceptibility Variant Curation Expert Panel, ClinGen (expert panel). (ClinVarID = 12964)
In silico
SpliceAI predicts no significant splice impact for this variant (max delta score = 0.02). REVEL score = 0.927. BayesDel score = 0.458335.
Somatic
This variant does not lie in a statistically significant hotspot. This variant has previously been reported in somatic cancers (COSMIC; COSV100616513, n = 1 times).
Cancer Hotspots
This variant does not lie in a statistically significant hotspot.