What is (are) Pycnodysostosis ?
Pycnodysostosis is a rare condition characterized by moderate short stature (1.35m to 1.5m), increased density of the bones (osteosclerosis/osteopetrosis), underdevelopment of the tips of the fingers with absent or small nails, an abnomal collarbone (clavicle), distinctive facial features including a large head with a small face and chin, underdeveloped facial bones, a high forehead and dental abnormalities. Pycnodysostosis is an autosomal recessive genetic condition.  The gene has been mapped to the same location as the gene for cathepsin K on chromosome 1q21.  The diagnosis of pycnodysostosis is based on physical features and X-ray findings.  Molecular genetic testing is available.  Management is symptomatic.  Individuals need orthopedic monitoring, treatment of fractures, appropriate dental care, and craniofacial surgery may be needed.