McKusick–Kaufman syndrome

McKusick–Kaufman syndrome (MKS) is a rare genetic condition caused by mutations in the MKKS gene, which affect how cells develop and function. It is named after Dr. Robert L. Kaufman and Victor McKusick, who studied the condition and helped identify key features.

MKS can be difficult to recognize in infancy because it resembles Bardet–Biedl syndrome (BBS). While MKS mainly causes extra fingers or toes (postaxial polydactyly), fluid buildup in the vagina (hydrometrocolpos), and heart defects, BBS has more severe symptoms such as vision loss and obesity that usually appear later in life.

MKS is most common in the Old Order Amish population, where it affects about 1 in 10,000 people. The syndrome was first discovered in this group through a genetic method called positional cloning, which helped scientists identify the MKKS gene as the cause of this condition. Its prevalence outside the Amish population remains unknown.