Pachyonychia congenita: a four generation pedigree

Pachyonychia congenita is a rare genodermatosis characterized by symmetrical thickening and discoloration of the nails with a wedge-shaped, pinched-up, or claw-like appearance. Subungual hyperkeratosis results in a lifting up of the free edge of the nail. Nail changes may be seen alone or in combination with a variety of other cutaneous findings. The authors present a kindred with fifteen cases of pachyonychia congenita in four generations, in Lebanon County, Pennsylvania.