Syndrome of the month

Abstract

Sclerosteosis is a severe autosomal recessive disorder in which progressive bone overgrowth leads to gigantism, cranial nerve entrapment, and raised intracranial pressure. About 60 affected persons have been documented, the vast majority in the Afrikaner population of South Africa. In addition, sporadic cases or affected sibs have been reported from the USA, Switzerland, Japan, and Brazil. Mandibular prognathism and frontal prominence become evident by the age of five years. These deformities progress and in adulthood the face is severly distorted, with dental malocclusion, proptosis, and relative mid-facial hypoplasia. Affected children are tall for their age and adults with the condition may have gigantism. The majority have partial or total syndactyly, usually of the second and third fingers, with deviation of the terminal phalanges and hypoplasia of the nails of the corresponding digits. The bones are resistant to trauma and fractures are infrequent. Transient palsy of the seventh cranial nerve occurs during infancy and bilateral facial paralysis is usually permanent by adulthood.