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Mitral valve prolapse (MVP) is a common finding with 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 one or both leaflets into the left atrium during systole. MVP2 (MIM 607829) is nonsyndromic and it has been shown to be caused by autosomal dominant mutations in the DCHS1 gene encoding protocadherin-16. Two other MVP loci have been mapped: MVP1 (MIM 157700) to chromosome 16p and MVP3 (610840) to chromosome 13q.

Mutations in DCHS1 can also cause Van Maldergem syndrome 1 (VMLDS1; MIM 601390). It is an autosomal recessive disorder characterized by craniofacial abnormalities, intellectual disability, skeletal abnormalities, and hearing loss due to auditory malformations. Craniofacial findings include hypertelorism, epicanthal folds, ptosis, broad nasal bridge, downturned mouth, flat midface, maxillary hypoplasia, and micrognathia. Skeletal findings consist of joint laxity, osteopenia, and limb deformities such as subluxation of the radial heads, clinodactyly, syndactyly, and talipes equinovarus. MRI findings include subcortical neuronal heterotopia, dysmorphic corpus callosum and simplified gyral pattern. VMLDS2 (MIM 615546) is clinically related to VMLDS1. It is also an autosomal recessive disorder caused by mutations in FAT4 gene.