Pyle disease (metaphyseal dysplasia).

Pyle disease is an innocuous autosomal recessive disorder in which mild clinical manifestations con- trast with the radiological appearances of gross metaphyseal undermodelling.The disorder was first reported by Pyle* in 19311 as "a case of unusual bone development", when he documented a boy aged five years who presented with knock knees.This child and his affected sister were restudied by Bakwin and Krida,2 who designated the disorder 'familial metaphyseal dysplasia'.Semantic confusion with craniometaphyseal dysplasia arose, but this issue was clarified when Gorlin et a13 4 emphasised the separate status of these entities.The term 'metaphyseal dysplasia' was used in the 1983 Paris Nomenclature and, in deference to popular convention, the eponym Pyle was added in brackets.About 20 cases of Pyle disease can be recognised in published reports and these are listed in the table.