We describe a three-generation family with an autosomal dominant hidrotic ectodermal dysplasia consisting mainly of tricho- and onychodysplasia. One of the patients had supraventricular tachycardia, another had palpitations, and two others had sinus brachycardia. We consider that the clinical manifestations in this family differ significantly from those of the Clouston syndrome (their previous diagnosis) and places them in Group A, subgroup 1-3 (tricho-onychic) of the ectodermal dysplasia classification proposed by Freire-Maia and Pinheiro [1988, "Ectodermal Dysplasias"].