The "Neglected Middle": Redefining HCM Genetics with Intermediate Effect Variants

In this episode of In the Thick of It, genetic counselor Matthew Thomas sits down with Dr. Roddy Walsh and Dr. Juan Pablo Ochoa to discuss their groundbreaking research on the genetic architecture of Hypertrophic Cardiomyopathy (HCM). The conversation centers on "Intermediate Effect Variants" (IEVs)—genetic markers that fall between rare, high-impact Mendelian mutations and common, low-impact polygenic risk factors. By utilizing a massive dataset of over 20,000 patients and robust ancestry-matched controls, the researchers demonstrate how these variants contribute to disease severity, age of onset, and wall thickness. This episode explores the practical implications for clinical genetic testing, the necessity of diverse genomic data, and how these findings are shifting the field toward a more quantitative and comprehensive understanding of HCM risk.References: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.125.074529