Although several excellent reviews of how focal dermal hypoplasia (FDH) syndrome may affect various organs and organ systems such as the eyes, the bones, the teeth, and the skin have been published, the last comprehensive review of this disorder appeared more than 20 years ago.1 In the meantime, a number of new clinical manifestations have been recognized and considerable knowledge has accumulated regarding the methods of inheritance and pathogenetic mechanisms. The purpose of this review is to gather together this more recent information.
More than 200 cases of FDH have been reported in the literature or are otherwise known. Thus, the disorder is not a particularly rare one, and new cases regularly come to light in medical journals, at meetings of the American Academy of Dermatology, at local society meetings, at medical school grand rounds, and in private office practices. Most cases are seen in female subjects, but more