Pachyonychia Congenita


PC is an ultra rare genetic skin disorder caused by a single mutation in one of at least four keratin genes including K6a, K6b, K16 or K17. PC may be hereditary (inherited from a parent who has PC) or may be spontaneous (a mutation occuring when no parent or other family member has PC).

Symptoms - Pachyonychia Congenita

Pachyonychia Congentita symptoms may include:

  1. Painful blisters and calluses on hands and feet (focal palmar and plantar hyperkeratosis)
  2. Thickened Nails (hypertrophic nail dystrophy or pachy-onychia)
  3. Follicular hyperkeratosis (bumps around hairs at friction sites such as waist, hips, knees, elbows)
  4. Cysts of various types (including steatocystoma and pilosebaceous cysts)

Other features include sores at the corner of the mouth (angular chelitis); teeth at or before birth (natal or pre-natal teeth); hoarse voice (laryngeal involvement). Note: Some with PC often suffer intense pain near the jaw or ears lasting 15-25 seconds when beginning to eat. This may be connected to salivary glands rather than to ears. More research is needed on this.

Causes - Pachyonychia Congenita

There are numerous different mutations that cause PC. Most medical literature offers two classifications of the mutations, known as PC-1 Jadassohn-Lewandowsky type and PC-2 Jackson-Lawler type. However, data collected from over 250 patients in the IPCRR (with genetically confirmed PC) clearly show that there are similarities and differences across all the genes and mutations. The genes do not pair up as described in medical literature into the two classifications. Therefore, reference to these subtypes does not assist in diagnosis or treatment and should be discontinued.

Prevention - Pachyonychia Congenita

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Diagnosis - Pachyonychia Congenita

PC can be diagnosed in two ways: by clinical diagnosis, or phenotype (where a physican makes a diagnosis based on the appearance of the features which the patient has), or by genetic diagnosis, or genotype (where the diagnosis is made based on determination of the specific mutation in the genes K6a, K16, K6b, and K17). However, reliance upon clinical diagnosis exclusively has led to misdiagnoses and even some confusion about the condition itself. Many articles written about 'pachyonychia congenita' written before genetic testing became available are actually about other diseases and about 10% of those diagnosed clinically with PC are found to not have PC based on the genetic findings. While clinical diagnosis is still important, genetic testing is the only way to verify that the patient's condition is in fact PC and not a related disorder.

Prognosis - Pachyonychia Congenita

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Treatment - Pachyonychia Congenita

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Resources - Pachyonychia Congenita

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Research Publications