Pachyonychia congenita: a case report.

A 21-year-old man presented with hypertrophic nail dystrophy and subungual debris of all 20 nails, hyperkeratotic plaques on the heels of both feet, and oral leukokeratosis. He had an extensive family history of similar clinical findings. The patient's clinical presentation and history were consistent with pachyonychia congenita (PC), an autosomal dominant genodermatosis caused by mutations in the genes for keratin 6, K6a and K6b; keratin 16, K16; and keratin 17, K17.