Which of these is not a single gene disorder?

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.