MYH7

About MYH7

MYH7 on chromosome 14q11.2 encodes beta myosin heavy chain, the motor protein that drives contraction in the ventricles of the heart and in slow twitch skeletal muscle fibers by using ATP to pull on actin filaments. It lies next to MYH6, which encodes the alpha isoform. Pathogenic MYH7 variants are, together with MYBPC3, the most common genetic causes of hypertrophic cardiomyopathy, a condition with an estimated prevalence of about 1 in 500 people, characterized by thickening of the left ventricular wall, often asymmetric and involving the septum, diastolic dysfunction, left ventricular outflow tract obstruction, arrhythmias, and a risk of sudden cardiac death in young people, including athletes. The R403Q missense variant, reported in 1990 by the laboratory of Christine and Jonathan Seidman, was the first gene defect identified in hypertrophic cardiomyopathy. Other MYH7 variants cause dilated cardiomyopathy, left ventricular noncompaction, and skeletal myopathies such as Laing distal myopathy and myosin storage myopathy. Family screening is commonly offered when a variant is found. Treatments include beta blockers, septal reduction procedures, implantable defibrillators for high risk patients, and mavacamten, a first in class cardiac myosin inhibitor that reduces excessive contractility.