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Genetic and Rare Diseases Information Center (GARD)

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Other Names for this Disease
  • PKND
  • PYCD
  • Pyknodysostosis
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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.[1][2] 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.[3]
Last updated: 7/1/2010


  1. Alves-Pereira, D., Berini-Aytes, L. and Gay-Escoda, C.. Med Oral Patol Oral Cir Bucal. Oct 2008; Accessed 1/1/1900.
  2. Pyknodysostosis. National Organization for Rare Disorders . Accessed 6/1/2010.
  3. Pycnodysostosis. Orphanet. December 2008; Accessed 6/30/2010.
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Basic Information

In Depth Information

  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs.  Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Pycnodysostosis. Click on the link to view a sample search on this topic.