Study of Skeletal Disorders and Short Stature

Overview

This study will determine the genes responsible for skeletal dysplasias (disorders of the skeleton) and short stature and define the range and type of medical problems they cause over time. It will investigate whether specific gene changes cause specific medical problems in these disorders and identify the signs and symptoms upon which their diagnoses must be based. Individuals with short stature or with a skeletal dysplasia known or suspected to be caused by a gene mutation (change) may be eligible for this study. Family members may also participate. Skeletal dysplasias under study include: achondroplasia, hypochondroplasia, achondrogenesis type II, hypochondrogenesis, Kniest dysplasia, spondyloepiphyseal dysplasias, Stickler syndrome; Shmid and Jansen metaphyseal dysplasias; pyknodysotosis, proximal symphalangism, brachydactyly types B C and E, Ellis van Creveld and related disorders, metatrophic chondrodysplasias, cartilage-hair hypoplasia and disorders with a skeletal abnormality that have not yet been defined but might be the result of a genetic defect. Patients will talk with two genetics specialists who will explain the study and its possible implications for the patient and family and answer questions. The patient's medical records will be reviewed, a personal and family history will be taken, and a physical examination will be done. Various other procedures that may be done include drawing up to 6 tablespoons of blood, some of which will be used for DNA (genetic) studies, X-rays, echocardiography (ultrasound of the heart), magnetic resonance imaging (MRI), eye examination, hearing test, sleep study, sperm analysis and skin biopsy (surgical removal of a small piece of skin done under local anesthetic). There may be additional evaluations by specialists in rheumatology, rehabilitation medicine and orthopedics. When the tests and examinations are completed (after 2 to 3 days), a doctor will discuss the results with the patient. Patients whose DNA studies show that a gene change is responsible for their disorder will meet with a genetics nurse or counselor to review the results, express their feelings and ask any questions they may have. Patients may be asked to return to NIH every 6 months to 2 years for continued follow-up. Medical management will be provided primarily by the patient's own physician. Participating family members will be interviewed by telephone about their personal and family health history and will have a blood sample drawn for DNA testing. If a gene change is found that is responsible for the bone disorder or growth problem in the family, arrangements will be made for the family member to discuss the implications of the findings with a genetics specialist.

We will investigate the clinical manifestations and molecular genetic defects of human skeletal dysplasias and generalized short stature. Families with skeletal dysplasias or short stature of known or suspected genetic basis will be enrolled. Affected individuals or individuals suspected of having a skeletal dysplasia will undergo periodic clinical assessment and genetic analyses for the purpose of: 1) definition and characterization of phenotype, 2) determination of the natural history of the disorder, and 3) genotype/phenotype correlation. Genetic linkage studies may be performed for disorders in which the genetic bases is not yet known.