Witkop tooth and nail syndrome is a rare autosomal dominant ectodermal dysplasia that affects teeth and nails. It is a result of the mutation of gene MSX1 on chromosome 4p16.1. The syndrome equally affects both males and females.

Primary teeth and nails may be absent beginning in infancy. Nails may also grow distinctively slowly until around age 2 or 3. However, the disorder is most often detected at approximately age 4 or 5.

Other typical dental manifestations include the absence of secondary teeth and malformation of both primary and secondary teeth. Nails are hypoplastic and may exhibit koilonychia and fragility. Toenails are typically affected with greater severity than fingernails, and nail manifestations improve with age.

Fine, brittle, slow-growing scalp hair may be present in some kindreds.