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Pachyonychia congenita

Other Names for this Disease
  • Congenital pachyonychia
  • Pachyonychia congenita syndrome
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Pachyonychia congenita (PC) is a very rare inherited condition that primarily affects the nails and skin. The fingernails and toenails are usually thickened and abnormally shaped. Affected individuals may also develop painful calluses and blisters on the soles of their feet and palms of their hands (palmoplantar keratoderma). Additional features include white patches on the tongue and inside of the mouth; bumps around the elbows, knees, and waistline; cysts in the armpits, groin, back, or scalp; and excessive sweating on the palms or soles of the feet. Features may vary among affected individuals.[1]

Two major types of this condition have been described: pachyonychia congenita type 1 (PC-1) and pachyonychia congenita type 2 (PC-2). PC is caused by a mutation in one of four genes. Mutations in the KRT6A and KRT16 gene cause PC-1; mutations in KRT6B and KRT17 result in PC-2.[1]
Last updated: 5/4/2011


  1. Pachyonychia congenita. Genetics Home Reference. August 2008; Accessed 5/4/2011.
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Basic Information

  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • Genetics Home Reference (GHR) contains information on Pachyonychia congenita. This website is maintained by the National Library of Medicine.

In Depth Information

  • Medscape Reference provides information on this topic. Click on the link to view this information. You may need to register to view the medical textbook, but registration is free.
  • 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 Pachyonychia congenita. Click on the link to view a sample search on this topic.