Familial hypertrophic cardiomyopathy (HCM) is characterized by a thickening of the heart muscle that can cause a restriction in the blood flow from the heart. Genetic analysis for familial HCM focuses primarily on genes that encode the sarcomere proteins. The MHI's Molecular Diagnostic Laboratory reports on five such genes in the first line of analysis: MYBPC3 (20-45%), MYH7 (15-20%), TNNT2 (1-7%), TNNI3 (1-7%) and TPM1 (2-5%), as well as two genes involved in lysosomial defects and presenting symptoms similar (phenocopy) to a HCM on the ECG: PRKAG2 and LAMP2. The percentage indicates the frequency of variants found in these genes. If no variant is identified in the first seven genes, 18 other genes are then analyzed, including the last four genes that encode a sarcomere protein. Collectively, these variants in those genes were found in approximately 60% of patients with a family history of HCM and 30% of patients with no family history. Approximately 3% of patients will show more than one variant, which could be associated with a more severe phenotype. The prevalence of HCM ranges from 1:200 to 1:500 according to the different sources.
PMID: 21787999, 2011
PMID: 21459272, 2011
PMID: 25814232, 2015
PMID: 26483113, 2015
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