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Pachyonychia congenita

Related Terms

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Background

  • Pachyonychia congenita (PC) is one of the ectodermal dysplasias, a group of syndromes deriving from abnormalities of the ectodermal structures, which include the hair, teeth, nails, sweat glands, cranial-facial structure, and hands. Ectodermal dysplasias are genetic disorders that can be inherited in an autosomal dominant or recessive manner.
  • While various classifications for PC have been proposed, only two forms of the condition are recognized: type I (PC-1) and type II (PC-2). However, there may be more types of PC, including type III (PC-3), and a form of PC that develops later in life, known as PC tarda, or PC late.
  • The signs and symptoms of PC typically appear within the first few months of life and include hypertrophic nail dystrophy, which causes the fingernails and toenails to become thickened and abnormally shaped; and palmoplantar keratoderma (painful calluses and blisters on the soles of the feet and, less commonly, on the palms of the hands). Other symptoms include oral leukokeratosis (thick, white patches on the tongue and insides of the cheeks); follicular keratoses, which are bumps that develop around hair follicles on the elbows, knees, and waistline; cysts in the armpits, groin, back, or scalp; and palmoplantar hyperhidrosis (excessive sweating on the palms and soles). Rarely, the condition can affect the larynx (voice box), potentially leading to hoarseness or breathing problems. These complications vary among affected individuals. PC-1 and PC-2 are distinguished by their genetic cause and by their signs and symptoms. Both types are associated with the features described above, but PC-2 has several additional signs that are not typically seen in PC-1. For example, most people with PC-2 develop widespread cysts called steatocystomas during puberty. People with PC-2 are also more likely to have twisted or kinked, brittle, and coarse hair. Additionally, some babies with PC-2 have prenatal or natal teeth, which are present at birth or in early infancy.
  • Pachyonychia congenita (PC) is a rare genetic disorder that is caused by a single mutation in any one of four keratin genes known as K6a, K6b, K16 or K17. K6a and K6b are located on chromosome 12, while K16 and K17 are located on chromosome 17. Keratin proteins are tough, insoluble, structural proteins that grow from the skin and include hair and nails. Mutations in keratin genes K6a or K16 cause PC-1, while mutations in keratin genes K6b and K17 cause PC-2. PC-1 is more common than PC-2.
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Risk Factors

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Causes

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Signs and Symptoms

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Types of the Disease

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Diagnosis

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Complications

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Treatment

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Integrative Therapies

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Prevention

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Author Information

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References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.