<prompt> Which of these is not a single gene disorder?Mitral Valve ProlapseHyperophic Obstructive CardiomyopathyDilated CardiomyopathyArrhythmogenic Right Ventricular Cardiomyopathy  <response>: Familial HCM, AD Mendelian inherited disease in approximately 50 of cases. Greater than 100 mutations have been identified in at least 12 sarcomeric genes with b-myosin heavy chain being most frequently affected, followed by myosin-binding protein C and troponin T. These three genes account for 70 to 80 of all cases of HCM. In Arrhythmogenic right ventricular dysplasia the ventricular wall is severely thinned as a result of myocyte replacement by massive fatty infiltration and lesser amounts of fibrosis. 