Pattern recognition in bone dysplasias.

Genetically different bone dysplasias may manifest themselves in similar patterns of skeletal abnormalities. It is proposed to group these similar dysplasias in 'families' for two reasons: 1 The knowledge of developmental patterns shared by different genetic disorders cautions the diagnostician and encourages a two-step procedure: a) provisional recognition of a pattern and b) more careful analysis of the pattern to reach a final, specific diagnosis. 2 Families of bone dysplasias may be the result of similar pathogenetic mechanisms. Once the mechanism is discovered in one member of the family, a search for similar mechanisms in others may be rewarding. An example of such a pattern is dysostosis multiplex. It is found in a family of disorders caused by defects of complex carbohydrate degradation. The present study delineates four more patterns and their families: the achondroplasia pattern, spondyloepiphyseal dysplasia congenita pattern, the Larsen/OPD pattern and the Stickler/Kniest pattern.