Oligodontia and curly hair occur with ectodysplasin-a mutations.

Oligodontia is the developmental absence of more than 5 permanent teeth except for the third molar. Familial oligodontia can occur as an isolated form or as part of a genetic syndrome. Mutations in the MSX1, PAX9, AXIN2, EDA, and WNT10A genes have been identified in familial non-syndromic oligodontia. Ectodermal dysplasia is a group of syndromes involving abnormalities of the ectodermal structures and is comprised of more than 150 different forms. Mutations in the ectodysplasin-A (EDA) gene have been associated with X-linked hypohidrotic ectodermal dysplasia, and partial disruption of the EDA signaling pathway has been shown to cause an isolated form of oligodontia. We identified 2 X-linked oligodontia families and performed mutational analysis of the EDA gene. The mutational analysis revealed 2 novel EDA mutations: c.866G>T, p.Arg289Leu and c.1135T>G, p.Phe379Val (reference sequence NM_001399.4). These mutations were perfectly segregated with oligodontia and curly hair within each family and were not found in the 150 control X-chromosomes with the same ethnic background and in the exome variant server. This study broadens the mutational spectrum of the EDA gene and the understanding of X-linked oligodontia with curly hair.