Genetic diseases with rheumatic manifestations in children.

Many nonrheumatic diseases of childhood present with musculoskeletal abnormalities. A significant proportion of these disorders have a genetic basis, many involving defects in structural proteins of the connective tissue. Chief among these are collagen mutations resulting in spondyloepiphyseal dysplasias and Ehlers-Danlos syndrome, as well as fibrillin defects associated with Marfan's syndrome. A variety of other chromosomal anomalies are associated with musculoskeletal abnormalities, and may result from as yet unidentified connective tissue defects. In addition, metabolic diseases may result in findings of hyper- or hypomobility, or carpal tunnel syndrome. Helpful clinical clues to identify nonrheumatologic musculoskeletal disease, as well as recent advances in our understanding of the genetic basis of several of these disorders, are reviewed here.