Complex polydactyly of the limbs: mirror foot. Report of two cases and review of literature

Polydactyly is the most common congenital limb anomaly occurring both as an isolated defect or as part of a syndrome. However mirror foot is an exceptional abnormality (14 cases reported). The authors describe two sporadic cases of mirror foot. The first case presents a mirror polydactyly of the left foot, an hexadactyly of the right foot and a central polysyndactyly of both hands. The second case presents a mirror polydactyly of both feet. Mirror foot is a very rare defect. Both sporadic and familiar cases have been reported. This malformation can affect one or both feet. Some cases are associated with other congenital anomalies. The definition of mirror foot is warying according to the authors and the review of literature shows an important variability in the patterns of mirror polydactyly. Mirror duplication of hands and feet result of aberrant positioning of the zone of polarizing activity in relation to the apical ectodermal ridge during limb bud development. Different genes encoding limb pattern have been described.