ClinVar

Description

Note this variant was found in clinical genetic testing performed by one or more labs who may also submit to ClinVar. Thus any internal case data may overlap with the internal case data of other labs. The interpretation reviewed below is that of the Stanford Center for Inherited Cardiovascular Disease. p.Tyr1100ValfsX49 (c. 3297dupG) in the MYBPC3 gene. We classify it as likely disease causing, based on the data reviewed below. The variant was re-reviewed February 17th, 2012. This variant is novel. The addition of Guanine at position 3297 causes a reading frame shift at codon 1100; as a result a premature stop codon is created 49 codons downstream. The amino acid sequence from codon 1100 to 1149 is changed, as well. The variant is expected to either cause a truncated MYBPC3 protein or a completely absent MYBPC3 protein due to nonsense-mediate mRNA decay. While this specific variant is novel, many other frameshift and null variants have been identified in MYBPC3 in association with cardiomyopathy (ex. p.Trp792fs, p.Pro794fs, p.Lys1065fs, p.Cys1202fs, p.Pro1208fs, p.Trp1098ter, p.Glu1096ter, p.Cys1124ter, p.Gln1233ter). The variant has not been seen in a total of 5200 laboratory controls and publicly available general population samples. The variant is not listed in the NHLBI Exome Sequencing Project dataset, which currently includes calls for MYBPC3 on ~5000 Caucasian and African-American individuals. Of note, there are no frameshift variants in that dataset. These if one nonsense variant, but it has been reported previously in association with HCM. There was no control data reported in the results. Upon request, GeneDx verbally provided control data on March 31st, 2011; the variant was not observed in 100 Caucasian control individuals (with high coverage) or 100 African American control individuals (with low coverage).