Mitral valve prolapse (MVP) has a prevalence of approximately 2 to 3% in the general population. It is characterized by fibromyxomatous changes in mitral leaflet tissue, with upward displacement of 1 or both leaflets into the left atrium during systole; MVP is diagnosed when the movement of the mitral leaflets exceeds 2 mm. In classic MVP, leaflets are at least 5 mm thick, whereas in nonclassic MVP, they are less than 5 mm thick. Auscultatory findings, when present, consist of a midsystolic click and/or a late systolic murmur. The natural history of MVP varies from benign, with a normal life expectancy, to severe complications associated with the development of significant mitral regurgitation, including congestive heart failure, bacterial endocarditis, atrial fibrillation, thromboembolism, and even sudden death. However, complications are uncommon, affecting less than 3% of individuals with MVP (Freed et al., 1999; Grau et al., 2007; Delling and Vasan, 2014). Grau et al. (2007) provided a detailed review of the genetics of mitral valve prolapse. Delling and Vasan (2014) reviewed the epidemiology and pathophysiology of MVP, with discussion of disease progression, genetics, and molecular basis. Genetic Heterogeneity of Familial Mitral Valve Prolapse The locus for MVP1 has been mapped to chromosome 16p; the locus for MVP2 (607829) has been mapped to chromosome 11p. Mitral valve prolapse-3 (MVP3; 610840) is caused by mutation in the DZIP1 gene (608671) on chromosome 13q32.