McKusick-Kaufman syndrome

McKusick-Kaufman syndrome, often shortened to MKS, is a rare genetic condition caused by mutations in the MKKS gene, which affect how cells develop and function. It is named for Robert L. Kaufman and Victor McKusick, who studied the condition and helped identify its key features. Its main features are extra fingers or toes on the little finger side of the hand or foot, a buildup of fluid in the vagina called hydrometrocolpos, and heart defects. In infancy it can be hard to tell from Bardet-Biedl syndrome, which brings more severe symptoms such as vision loss and obesity later in life. The syndrome is most common among the Old Order Amish, at about one in ten thousand, and it was first found there by positional cloning, which identified the MKKS gene. Its frequency outside that population is unknown.