Mavacamten is a first-in-class, selective allosteric inhibitor of cardiac myosin adenosine triphosphatase (ATPase) that has emerged as a novel therapeutic option for patients with symptomatic hypertrophic obstructive cardiomyopathy (HOCM) who remain refractory to conventional therapy, such as beta-blockers and calcium channel blockers. This evidence concerns the gene DNAH8 and hypertrophic cardiomyopathy.