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Pachyonychia congenita in Child
See also in: Nail and Distal Digit
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Pachyonychia congenita in Child

See also in: Nail and Distal Digit
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Contributors: Shari Lipner MD, PhD, Susan Burgin MD, Bertrand Richert MD, Robert Baran MD
Other Resources UpToDate PubMed

Synopsis

Pachyonychia congenita (PC) is one of a group of hereditary palmoplantar keratodermas (PPKs) characterized by hypertrophic nail dystrophy and nail bed hyperkeratosis. Associated findings are palmoplantar keratoderma, oral leukokeratosis, pilosebaceous cysts, and follicular keratoses involving the trunk and extremities. Usually inherited in an autosomal dominant fashion, PC results from mutations in the genes encoding epidermal keratinocyte keratins and is usually noticed within the first months of life. An autosomal recessive form has also been described.

PC is classified into 4 subtypes:
  • Type 1 (also known as Jadassohn-Lewandowski syndrome) (keratin-16 gene mutation) is the most common subtype, representing 56% of PC patients. Patients present with subungual hyperkeratosis and progressive thickening of the fingernails and toenails beginning a few months after birth. The distal third of the nail plate is thickened with increased transverse curvature. Onycholysis is secondary to subungual hyperkeratosis. Patients often present with palmoplantar hyperkeratosis, follicular hyperkeratosis, and oral leukokeratoses.
  • Type 2 (also known as Jackson-Lawler syndrome) (keratin-17 gene mutations) account for 25% of patients with PC. In addition to the findings seen in PC type 1, type 2 patients present with bullae and hyperhidrosis of the palms and soles, natal teeth, and steatocystoma multiplex.
  • Type 3 patients (keratin-6A gene mutations), in addition to type 1 findings, also present with angular cheilitis, corneal dyskeratosis, and cataracts. These patients account for 12% of PC cases.
  • Type 4 patients (keratin-6B gene mutations), in addition to type 1 findings, also present with laryngeal lesions, hoarse voice, intellectual disability, and alopecia. These patients account for 7% of PC cases.
For more information, see OMIM.

Codes

ICD10CM:
Q84.5 – Enlarged and hypertrophic nails

SNOMEDCT:
39427000 – Pachyonychia congenita syndrome

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Last Reviewed: 12/11/2018
Last Updated: 01/14/2019
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Pachyonychia congenita in Child
See also in: Nail and Distal Digit
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Pachyonychia congenita (Type 1) : All twenty nails or distal digits, Subungual hyperkeratosis, Nail thickening
Clinical image of Pachyonychia congenita
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