Hay-Wells syndrome is a form of ectodermal dysplasia, a group of conditions characterized by abnormal development of ectodermal tissues including the skin, hair, nails, teeth, and sweat glands. The most common feature is missing patches of skin (erosions) on the scalp, neck, hands, and feet. The skin erosions can lead to infection, scarring, and hair loss. Other features include changes in skin coloring; misshapen or absent fingernails and toenails; malformed or missing teeth; increased sensitivity to heat; hearing loss; cleft lip and/or palate; and other facial abnormalities. This condition is caused by mutations in the TP63 gene and is inherited in an autosomal dominant fashion. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.