Twenty nail dystrophy in identical twins.

Twelve-year-old identical female twins have had lifelong twenty nail dystrophy. There is no evidence of other skin disorders. The condition has remained unchanged and has been unresponsive to a wide range of therapies. The benign clinical course of their nail disorder suggests twenty nail dystrophy may not be related to lichen planus or other cutaneous diseases. One of the causes of twenty nail dystrophy of childhood may be a localized tissue malformation, analogous to inflammatory linear verrucous epidermal naevus.