The natural histories of bone dysplasias in adults--vignettes, fables and just-so stories.

The bone dysplasias are a heterogeneous group of disorders arising from intrinsic abnormality of bone and cartilage growth and function. All are genetic. Most result in extreme small stature (dwarfism). Historically, emphasis was primarily on diagnostic identification of specific disorders in infants (including differentiating lethal and non-lethal forms), and on the clinical history to be anticipated in infants and children with each of these specific processes. Even in children there is exceedingly limited information of quality and virtually no controlled studies of the effects of intervention. For the most part, information about affected adults is even less complete and even less rigorous. Presented here are a series of examples of medical and adaptive issues in adults affected by one or another of the genetic skeletal dysplasias. Topics discussed include: approach to adults with no specific diagnosis; medical issues that cross diagnostic boundaries (osteoarthritis in the "E" disorders, obstructive apnea, issues in pregnancy in women with dwarfing disorders, activities of daily living, and quality of life assessments); diagnosis-specific problems of adulthood (spinal stenosis in achondroplasia, hearing loss in osteogenesis imperfecta, and malignancy risk in multiple exostoses); adult problems that must be addressed in childhood in order to be prevented (achondroplasia and kyphosis, and cervical spine abnormalities in Morquio syndrome); survival conundrums (why some live unexpectedly and others die unexpectedly). Emphasis is placed on the difficulties intrinsic to trying to learn about needs and expectations in generally rare genetic processes.