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BRAF
Final classification
VUS
BRAF c.1661T>C · p.Ile554Thr
BRAF

NM_004333.5:c.1661T>C (p.Ile554Thr) is a missense variant in BRAF exon 13, located in the kinase domain between the P-loop and CR3 activation segment.

Gene
BRAF
Transcript
NM_004333.5
HGVS · transcript:coding
NM_004333.5:c.1661T>C
Consequence
N/A
GRCh38
chr7:140776945 A>G
GRCh37
chr7:140476745 A>G
Basis ClinGen RASopathy Expert Panel Specifications to the ACMG/AMP Variant Interpretation Guidelines for BRAF Version 2.3.0 v2.3.0 criteria-combination framework was evaluated deterministically with applied criteria: PP2 supporting, PP3 supporting; no rule matched the adjudicated criteria.
ClinGen RASopathy Expert Panel Specifications to the ACMG/AMP Variant Interpretation Guidelines for BRAF Version 2.3.0 v2.3.0 criteria-combination framework was evaluated deterministically with applied criteria: PP2 supporting, PP3 supporting; no rule matched the adjudicated criteria.
Classification rationale
PP2PP3 VUS
BRAF c.1661T>C

NM_004333.5:c.1661T>C (p.Ile554Thr) is a missense variant in BRAF exon 13, located in the kinase domain between the P-loop and CR3 activation segment. This variant is present at extremely low frequency in population databases: gnomAD v2.1 AF=3.98e-6 (1/251,340 alleles) and v4.1 AF=1.43e-5 (23/1,613,478 alleles), with no homozygotes observed.1 ClinVar reports conflicting interpretations: Likely benign (2 clinical laboratories) and Uncertain significance (1 clinical laboratory), with no expert panel review (ClinVar Variation ID 239870).2 PP3 (supporting): REVEL score of 0.885 exceeds the VCEP threshold of ≥0.7 for pathogenic computational prediction. SpliceAI predicts no splicing impact (max delta 0.00).3 PP2 (supporting): BRAF has a high missense constraint Z-score in gnomAD (>3.09), indicating a low rate of benign missense variation consistent with a gene where missense variants are a common disease mechanism.4 PM1 is not met because amino acid 554 lies outside the VCEP-specified domains (exon 6, exon 11, P-loop AA 459-474, CR3 activation segment AA 594-627).5 PM2 is not met because the RASopathy VCEP requires absence from gnomAD controls, and this variant is observed in both gnomAD v2.1 and v4.1.6 PM5 is not met because no other [likely] pathogenic missense variant at codon 554 was identified in ClinVar or the VCEP supplementary materials.7 BS1 is not met because the allele frequency (max 9.92e-5) is below the VCEP threshold of ≥0.025%.8 No benign criteria are met. Two pathogenic supporting criteria (PP2, PP3) are met. Under the RASopathy VCEP v2.3.0 combination rules, this does not reach the threshold for Likely Pathogenic (which requires at minimum 1 moderate + 4 supporting, or 1 strong + 1 moderate, or comparable combinations).9 Insufficient evidence exists to classify this variant as either pathogenic or benign. With only two supporting-level pathogenic criteria and no benign criteria, this variant is classified as a Variant of Uncertain Significance (VUS).

PP2 + PP3 VUS
Gene diagram · NM_004333.5 · variants mapped to exon structure
BRAF NM_004333.5
Fetching transcript structure from UCSC…
Applied criteria · 2 met · select any tile
Met
Not met
Not assessed
N/A
Strength very strong supporting
Pathogenic evidence
PVS
PS
PM
PP
Benign evidence
BA
BS
BP
Rationale
Select a criterion.
Sources
Evidence used
    Gaps remaining
      Rule
      Research & evidence
      Population frequency
      gnomAD v4.1 screenshot
      gnomAD v4.1
      gnomAD v2.1 screenshot
      gnomAD v2.1
      v4.1
      This variant is present in gnomAD v4.1 (AF= 1.42549e-05; MAF= 0.00143%, 23/1613478 alleles, homozygotes = 0) and has highest observed frequency in the Ashkenazi Jewish population (AF= 3.37883e-05; MAF= 0.00338%, 1/29596 alleles, homozygotes = 0); grpmax FAF= 8.78e-06.
      v2.1
      This variant is present in gnomAD v2.1 (AF= 3.97867e-06; MAF= 0.00040%, 1/251340 alleles, homozygotes = 0) and has highest observed frequency in the Ashkenazi Jewish population (AF= 9.92063e-05; MAF= 0.00992%, 1/10080 alleles, homozygotes = 0).
      🇨🇦 CA
      Absent from gnomAD-Canada v1.0.
      Allele frequency by ancestry
      three datasets · side by side
      gnomAD v4.1
      0.0014% · 23 / 1,613,478
      0 hom · FAF 0.00088%
      Ashkenazi Jewish
      1 / 29,596
      0.0034%
      South Asian
      3 / 91,064
      0.0033%
      African/African American
      2 / 74,912
      0.0027%
      European (non-Finnish)
      17 / 1,179,872
      0.0014%
      + 6 not observed (Remaining individuals, Admixed American, European (Finnish), Amish, East Asian, Middle Eastern)
      gnomAD v2.1
      0.0004% · 1 / 251,340
      0 hom
      Ashkenazi Jewish
      1 / 10,080
      0.0099%
      + 7 not observed (African/African American, Admixed American, East Asian, European (Finnish), European (non-Finnish), Remaining individuals, South Asian)
      gnomAD Canada 🇨🇦
      Absent · 0 / ?
      0 hom
      Not observed in any ancestry group.
      ClinVar screenshot
      ClinVar
      This variant has been reported in ClinVar as Likely benign (2 clinical laboratories) and as Uncertain significance (1 clinical laboratory). (ClinVarID = 239870)
      SpliceAI screenshot
      In silico
      SpliceAI predicts no significant splice impact for this variant (max delta score = 0.00). REVEL score = 0.885. BayesDel score = 0.301041.
      Functional / OncoKB screenshot
      Functional Unknown Oncogenic Effect
      OncoKB did not identify variant-specific reviewed functional evidence for this variant; gene-level curated context is available for reviewer follow-up. BRAF, an intracellular kinase, is frequently mutated in melanoma, thyroid and lung cancers among others.
      OncoKB ↗
      COSMIC screenshot
      COSMIC
      Cancer hotspots screenshot
      Cancer hotspots
      Somatic evidence Not in COSMIC / hotspots
      COSMIC
      This variant does not lie in a statistically significant hotspot. This variant has previously been reported in somatic cancers (COSMIC; COSV56430604, n = 2 times).
      Hotspots
      This variant does not lie in a statistically significant hotspot.
      Sources & reference links
      9Sources
      CSpec VCEP
      ClinVar
      gnomAD v2.1
      gnomAD v4.1
      gnomAD-Canada
      SpliceAI
      OncoKB
      COSMIC
      Cancer hotspots
      Triaged references · 3 PMIDs not cited in assessment
      25741868 ↗ 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. CLINVAR
      20301680 ↗ HRAS-Related Costello Syndrome. CLINVAR
      25173338 ↗ 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). CLINVAR