Ectodermal dysplasia is a group of genetic conditions that affect the development of the skin, hair, nails, teeth, and sweat glands. It is caused by a mutation in one of several genes that are responsible for the development of these structures. Symptoms vary depending on the type of ectodermal dysplasia, but can include thin, sparse hair; dry, scaly skin; and missing or malformed teeth. In some cases, the sweat glands may be underdeveloped or absent, leading to an inability to regulate body temperature. Treatment typically involves managing the symptoms and may include the use of wigs, artificial nails, and dental prosthetics.