Disease Directory Pachyonychia Congenita
Dermatological

Pachyonychia Congenita

Also known as: PC, keratin nail thickening, PC-1, PC-2, keratin mutations

Prevalence

Less than 1 in 1,000,000

Onset

Congenital or early infancy

Type

Autosomal dominant

Gene

KRT6A, KRT6B, KRT16, KRT17

About Pachyonychia Congenita

Pachyonychia congenita is an ultrarare autosomal dominant keratin disorder caused by heterozygous mutations in one of four keratin genes — KRT6A, KRT6B, KRT16, or KRT17 — which encode keratins expressed in nail bed, palmoplantar epidermis, and oral mucosa. The hallmark feature is severe, wedge-shaped hypertrophic nail dystrophy present from birth or early infancy, accompanied by highly debilitating plantar keratoderma that causes extreme pain with weight-bearing and is considered the greatest determinant of quality of life impairment. The International Pachyonychia Congenita Research Registry (IPCRR) has been instrumental in characterising the natural history of this condition.

Common Clinical Features

Severe, wedge-shaped subungual hyperkeratosis affecting all twenty nails, often with nail shedding Focal plantar keratoderma with intensely painful blisters and calluses, causing significant gait impairment Oral leukokeratosis: white mucosal thickening of the tongue, cheeks, and gingiva from infancy Follicular hyperkeratosis (keratosis pilaris-like) on the trunk and extremities Natal or neonatal teeth in KRT17-related (PC-2) subtype Epidermal cysts (pilosebaceous cysts) particularly in KRT17 subtype Laryngeal involvement and hoarseness in some patients due to mucosal keratin abnormalities

Clinical Trial Eligibility Tips

What to know before applying to Pachyonychia Congenita trials.

The PC Project maintains the International Pachyonychia Congenita Research Registry (IPCRR) — enrolment in the registry is often a prerequisite for or facilitates entry into sponsored trials.

Eligibility frequently requires genotypic subtyping (PC-6A, PC-6B, PC-16, PC-17 based on gene affected) — confirm which keratin gene is mutated and obtain the exact variant notation.

Pain severity scoring (VAS or NRS) and plantar keratoderma grading are standard outcome measures; document baseline plantar pain levels and impact on ambulation before screening visits.

Patient Resources

Patient Organization

PC Project

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Natural History Registry

International Pachyonychia Congenita Research Registry

Join registry ↗

Orphanet

European reference resource for rare diseases (ORPHA:674)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting Pachyonychia Congenita trials

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