EDA and X-linked hypohidrotic ectodermal dysplasia: XLHED is caused by alterations in the ectodysplasin-A (EDA) gene (Kere et al. 1996), but there are also autosomal dominant, recessive and unknown mutations that cause an ED phenotype (Pinheiro and Freire‐Maia 1994; Munoz et al. 1997; Ho et al. 1998; Monreal et al. 1999).