Mutations in the EDA gene are responsible for X-linked hypohidrotic ectodermal dysplasia and hypodontia in Chinese kindreds.

X-linked hypohidrotic ectodermal dysplasia (XLHED, OMIM 305100) is a rare congenital disorder that results in the defective development of teeth, hair, nails, and eccrine sweat glands. Previous studies found that mutations in the ectodysplasin A (EDA) gene are associated with XLHED. In the present study, we investigated four Chinese families suffering from classical XLHED and investigated two additional families segregating hypodontia in an X-linked recessive manner. Mutations were characterized respectively in the EDA gene in all families, and five of these mutations were found to be novel. Among these mutations, five were missense (c.200A>T, c.463C>T, c.758T>C, c.926T>G, and c.491A>C) and located in the functional domain of EDA, and one was a splice donor site mutation in intron 5 (c.IVS5 + 1G>A), which may result in an alternative transcript derived from a new cryptic splice site. Our data further confirm that EDA mutations could cause both XLHED and isolated hypodontia and provide evidence that EDA is a strong candidate gene for tooth genesis.