Reasoning
The BRAF VCEP makes PS4 applicable to autosomal-dominant cases with RASopathy phenotypic specifications and assigns strength from points. The available literature concerns somatic cancer cohorts, not germline RASopathy patients: PMID:12198537 reports one BRAF K600E/K601E-equivalent tumor among 330 colorectal tumors, and PMID:22608338 reports two K601E melanoma patients in a treatment study. Neither provides a germline RASopathy case-control comparison, unaffected-control count, or VCEP PS4 point assignment. The available gnomAD observation is one allele among 1,612,884 alleles in v4.1, but no comparable affected RASopathy case frequency is available; therefore an OR and confidence interval cannot be validly calculated for this criterion.
VCEP rule
Strength adjustment using point-based scoring for autosomal dominant cases with phenotypic specifications: full points awarded with RASopathy phenotypes, reduced points applicable to cases with minimal phenotypic information (i.e. prenatal cases, cases with a clinical order of a RASopathy panel without clinical information, and cases with limited clinical information in other global tests (such as WES)). ... The prevalence of the variant in affected individuals is significantly increased compared to the prevalence in controls. ... ≥5 points. ... ≥3 points. ... ≥1 points.
Evidence considered
- VCEP PS4 rule: "Strength adjustment using point-based scoring for autosomal dominant cases with phenotypic specifications: full points awarded with RASopathy phenotypes, reduced points applicable to cases with minimal phenotypic information (i.e. prenatal cases, cases with a clinical order of a RASopathy panel without clinical information, and cases with limited clinical information in other global tests (such as WES))."
- VCEP PS4 rule: "The prevalence of the variant in affected individuals is significantly increased compared to the prevalence in controls."
- VCEP PS4 strength thresholds: "≥5 points." for Strong, "≥3 points." for Moderate, and "≥1 points." for Supporting; no applicable point total is available.
- PMID:12198537, Results paragraph and Table 1: one A–G transition at nucleotide 1,798 producing K600E under that paper's numbering, in a cohort of 330 colorectal tumours including 32 BRAF-mutant tumours; this is a somatic tumor observation, not a germline RASopathy case-control series.
- PMID:22608338, Results/Tumour Response and Discussion: two melanoma patients with K601E had progression-free survival of 1.5 and 4.2 months and no responses; this is a somatic treatment cohort, not a RASopathy prevalence comparison.
- gnomAD v4.1: 1 observed allele among 1,612,884 alleles (AF 6.20007e-07), with no matched affected RASopathy numerator or denominator available for an OR and 95% CI.
Still missing
- Germline RASopathy case count and phenotype-specific cohort denominator
- Matched unaffected/control count or case-control table
- VCEP PS4 phenotype-specific point assignment
Sources