E - Beta myosin heavy chain is the protein that is most likely to cause the thickening of the ventricle described above. This is a major protein produced by the MYH7 gene and comprises the thick filament in cardiac muscle and plays a major role in cardiac muscle contraction. Mutations of this MYH7 cause excess thickening of the cardiac muscle, namely the left ventricle wall. It is not known how the mutation of MYH7 causes this thickening, but this thickening causes a functional impairment of the cardiac muscle. This thickening is found in those with hypertrophic cardiomyopathy (HCM), which is the leading cause of death in young athletes. Approximately 50-60% of patients with a high clinical risk for HCM have a mutation in their sacromeric
