Objective: To analyze the clinical phenotype and MYH7 gene variant in a Chinese pedigree affected with hypertrophic cardiomyopathy (HCM).
Methods: The proband was screened for variant of 96 cardiomyopathy-associated genes by exonic amplification and high-throughput sequencing. Candidate variant was verified by Sanger sequencing among 300 healthy controls as well as family members of the proband. Co-segregation analysis of genotypes and clinical phenotypes was carried out for the pedigree. Clustal X software was used to analyze the sequence conservation of the variant among various species, and its pathogenicity was predicted by using bioinformatics software.
Results: 6 out of 12 members from this pedigree were found to harbor heterozygous c.4124A>G (p.Tyr1375Cys) variant of the MYH7 gene, among whom five were diagnosed with HCM. The remaining one had failed to meet the diagnostic criteria for HCM, but had abnormal ECG. The same variant was not found in the 300 healthy controls. Amino acid sequence analysis showed that the variant is located in a highly conserved region, and bioinformatics analysis predicted that this variant may affect protein function and has a deleterious effect. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, the variant was predicted to be likely pathogenic (PM2+ PP1_Moderate+PP3+PP5).
Conclusion: The c.4124A>G (p.Tyr1375Cys) variant of the MYH7 gene probably underlay the pathogenesis in this pedigree. Above finding has important value for the early diagnosis of patients with HCM.