Rapp-Hodgkin syndrome (RHS) is characterised by the association of anhidrotic ectodermal dysplasia with cleft lip/palate. The syndrome is usually evident at birth but the prevalence is unknown with less than 100 cases reported in the literature so far. The ectodermal dysplasia is characterised by sparse, brittle, and dry hair with alopecia in adulthood together with hypohidrosis and heat intolerance, dental anomalies (hypodontia, cone-shaped incisors and enamel hypoplasia) and dysplastic nails. Hypospadias in males, obstructed lacrimal puncta or epiphora, and a characteristic facies (maxillary hypoplasia, small mouth, thin upper lip and narrow nose) have also been reported. RHS is transmitted as an autosomal dominant trait as is caused by mutations in the gene encoding the p63 transcription factor (also known as the tumor protein p73-like (TP73L) gene, localised to 3q27). RHS shows significant clinical overlap with other ectodermal dysplasia-clefting syndromes, principally ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome (see this term), which is also caused by mutations in the p63 gene. This has led to the suggestion that RHS and AEC represent variable expression of the same clinical entity. However, RHS and AEC can be distinguished by the presence of ankyloblepharon in AEC syndrome and the low frequency of scalp dermatitis in RHS. There is no treatment for RHS but management of patients usually revolves around correction of the cleft lip/palate and dental anomalies.
Last update: November 2006