Modifier genes for hypertrophic cardiomyopathy

Area of Science:

• Cardiovascular Genetics
• Molecular Cardiology
• Genetic Epidemiology

Background:

• Over 100 mutations in sarcomeric proteins and other genes are linked to hypertrophic cardiomyopathy (HCM).
• Significant variability in HCM phenotype expression exists even among patients with identical causal mutations.
• Genetic background, through modifier genes, plays a substantial role in HCM phenotype variability.

Purpose of the Study:

• To highlight the significant role of modifier genes in hypertrophic cardiomyopathy (HCM) phenotype expression.
• To emphasize the need for large-scale genome-wide and candidate gene approaches to identify HCM modifier genes.
• To underscore the potential of identifying modifier genes for improved diagnosis, risk stratification, and therapeutic strategies in HCM.

Main Methods:

• Review of genotype-phenotype correlation studies in hypertrophic cardiomyopathy (HCM).
• Analysis of polymorphism association studies, focusing on single nucleotide polymorphisms in cardiac growth genes.
• Exploration of candidate gene approaches, including genes in the renin-angiotensin-aldosterone system.

Main Results:

• Causal mutations account for only a fraction of HCM phenotype variability.
• The angiotensin-1 converting enzyme 1 gene insertion/deletion polymorphism is commonly implicated, affecting sudden cardiac death risk and hypertrophy severity.
• Therapeutic targeting of modifier genes has shown promise in animal models of HCM.

Conclusions:

• Modifier genes significantly impact the expression of cardiac phenotype in hypertrophic cardiomyopathy (HCM).
• Identification of modifier genes is essential to complement causative gene studies.
• Understanding modifier genes can enhance genetic diagnosis, risk stratification, and preventive/therapeutic measures for HCM patients.