A Four Generation Hidrotic Ectodermal Dysplasia Family: An Allelic Variant of Clouston Syndrome?

The study described a four-generation Scottish family with hidrotic ectodermal dysplasia, primarily affecting teeth, skin, and hair. Key features included hypo- or oligodontia by late adolescence, with some individuals having multiple natal teeth. Some women exhibited flexural acanthosis nigricans during childhood and early adolescence. All affected individuals could sweat, but heat tolerance varied. Scalp hair was thin and slow-growing, though adult females reported improved hair quality during pregnancy, and body hair was scanty. Abnormal cuticular appearances in hair samples suggested a primary keratin structure defect. Nails were normal, and relative macrocephaly due to cranial vault hyperostosis was variably present. Short stature was noted in some cases. The family showed overlapping features with Clouston syndrome, but with differences such as less severe alopecia and the absence of prominent palmarplantar hyperkeratosis and hypo/oligodontia.