 Consequently, in addition to tragedy involving an athlete who succumbs, there are medical implications for close relatives.Among family members of index cases, more than 300 causative mutations have been identified.However, not all mutations have the same potential for severe outcomes, and there is not yet a clear understanding of how these mutations (which affect the same myosin protein molecule) can lead to the dramatically different clinical characteristics and outcomes associated with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM).