Résumé : Coexistence of polydactyly and ectrodactyly in a sibship of four children is reported. One boy and one male twin presented polydactyly, the male monozygotic cotwin had a lobser claw deformity of the right foot and the last child, a girl, had absence of the phalanges of the right hand. Embryological explanation of these apparently totally opposed malformations is attempted.