Syndactyly/brachyphalangy and nail dysplasias as marker lesions for sclerosteosis

Sclerosteosis describes an autosomal recessive form of hyperostosis cortica llis generalisata (MIM 239100). Sclerosteosis is primarily a disorder of os teoblast hyperactivity and metabolic abnormalities are not present. Besides generalized bone changes the presence of asymmetric cutaneous syndactyly o f the index and middle fingers is characteristic. In many cases this syndac tyly is associated with nail dysplasia and therefore dermatologists should recognize this clinical finding as a possible marker of this entity. We rep ort on a 36-year-old female of Greek origin who had had finger and nail dys plasias and facial asymmetry since birth. The patient was hospitalized on t he Neurology ward because of increasing spastic and ataxic gait disturbance s. Physical examination revealed numerous neurological problems resulting f rom bony compression of nerves. Furthermore the patient had remarkably defo rmed fingers with hypoplasia of the second finger on both sides. The nails were dysplastic, especially on both index fingers. All laboratory results c oncerning metabolic diseases were normal. It has been shown that sclerosteo sis is clinically and radiographically very similar to van Buchem disease. Through a genome-wide search with a highly polymorphic microsatellite the g ene responsible for van Buchem disease has been mapped to 17q12-q21, and Ba lemans et al. (1999) assigned the locus for sclerosteosis to the same regio n providing genetic support for the hypothesis of allelism. Dermatologists should be able to interpret such syndactyly associated with nail deformitie s as a possible hint for the diagnosis of sclerosteosis in patients with hy perostotic features. Copyright (C) 2001 S. Karger AG, Basel.