ClinVar

Description

Variant summary: STXBP2 c.1621G>A (p.Gly541Ser) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00023 in 248156 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in STXBP2 causing Familial Hemophagocytic Lymphohistiocytosis (0.00023 vs 0.0022), allowing no conclusion about variant significance. c.1621G>A has been reported in the literature as biallelic homozygous or compound heterozygous genotypes in multiple individuals affected with Familial Hemophagocytic Lymphohistiocytosis (example, Cetica_2010, Pagel_2012). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (Cetica_2012). The most pronounced variant effect results in a defective protein and by defective cytotoxicity by T lymphocytes. Nine clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic.