Mixed polydactyly. An unusual case of a patient with seven-toed feet.

Polydactyly is an entity of great etiologic heterogeneity, and many facts about its genetics remain unknown. Therefore, the relative terminology and classification in the literature are rather obscure. Mixed polydactyly, i.e., polydactyly with both preaxial and postaxial involvement in the same person, is very rare, and crossed polydactyly is even more so. A seven-year-old girl with six fingers on each hand and seven-toed feet, lower-mixed and crossed polydactyly with syndactyly, underwent operation mainly for cosmetic reasons. The report of this rare case confirms the great variability and expressivity of this malformation and suggests that large statistical studies on this subject in the future are warranted.