The following report is that of a case of hereditary ectodermal dysplasia in a boy, 3½ years of age. He presented multiple defects involving tissues that have their origin in the embryonic ectoderm, namely, the hair, the teeth and the nails of the fingers and toes, as well as evidences of mental retardation.
We shall not enter into a discussion of the etiology of the disorder or attempt a review of the literature. These aspects are discussed in an excellent paper by Weech,1 who collected nine cases of hereditary ectodermal dysplasia from the literature and described two others observed by himself. We wish to call attention, however, to two more recent publications on the subject, one by Clouston2 and another by Smith.3 In the paper by Smith, a review of the entire subject is given with a summary of the characteristics of fifteen cases, to which number