Tooth and nail syndrome

Tooth and nail syndrome is a rare inherited disorder that affects the nails and the teeth. Its best known feature is nails that are thin, small and fragile and that may show koilonychia, an upward spooning of the nail, from birth. It is also called hypodontia with nail dysgenesis, Witkop syndrome and mucoepithelial dysplasia syndrome, and it is classed as an autosomal dominant form of ectodermal dysplasia. The condition is associated with the MSX1 gene, and its estimated incidence is about 2 in 10,000 people. It was first described in 1965, and the name Witkop honors Dr. Carl J. Witkop Jr., who is credited with describing it between 1978 and 1982.