Congenital malalignment of the great toenails in a pair of monozygotic twins.

Congenital malalignment of the great toenails is the lateral deviation of the long axis of nail growth relative to the distal phalanx. The nails grow slowly, with thickening, curving, and transverse ridging. We describe a pair of 3-year-old monozygotic female twins with congenital malalignment of the great toenails complicated by ingrowing and paronychia. Although there are a few cases without any family history, congenital malalignment is believed to be inherited through an autosomal-dominant gene of variable expression. This report provides further evidence of the heritability of the disease.