Cohen Syndrome is a genetic condition caused by mutations in the VPS13B gene. Patients who have Cohen Syndrome have vision problems (retinal dystrophy and high myopia), a small head size (microcephaly), developmental delay, flexible joints, characteristic facial features, obesity of the midsection with slender extremities, overly social behaviour, and low white blood cells (neutropenia). Approximately 200 affected individuals have been reported to date.

Cohen Syndrome is inherited in an autosomal recessive manner. At conception, each sibling of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk relatives and prenatal testing for pregnancies at increased risk are possible if the VPS13B mutations present in the family have been identified.