Dizygotic twins with congenital malalignment of the great toenails: reappraisal of the pathogenesis.

Congenital malalignment of the great toenails (CMGTN) is a heritable disorder, in which the longitudinal axis of the nail plate is not parallel to the corresponding axis of the distal phalanx of the hallux, but laterally deviated. We describe a pair of 1(1/2)-month-old dizygotic twins with laterally deviated nail plates of the great toenails since birth. By the time the infants were 10 months of age, significant realignment was observed. Adult pedigree members also showed slight similar deviations of the nail plates. We suggest that desynchronization of growth between the nail and the adherent end-phalanx of the hallux may result in temporarily larger nail plates, which are gliding outwards, in order to fit into the underlying bony space. During postnatal life, spontaneous realignment is usually observed, probably as a result of a faster growing end-phalanx.