Three sibs with Roberts syndrome SC-phocomelia are presented. The first one, a nine years old girl, with a malformative syndrome consistent with SC-phocomelia: symmetrical reductive malformations of the upper limbs; flexion contractures of both knee joints; multiple minor anomalies, including hemangioma of the face, hypoplastic nose, dysplastic ears and scanty, silvery blond hair; intrauterine and extrauterine growth retardation; psychomotor and mild mental retardation. Cytogenetic study reveals a centromeric abnormality consistent with an unusual sister chromatid disjunction in all metaphases, that can also be a useful tool in prenatal diagnosis. Next two sibs were males and offspring of a twin pregnancy and were found to have a malformative syndrome consistent with Roberts syndrome: low birth weight; dysplastic ears; hypertelorism, exophthalmos and cloudy corneas; bilateral cleft lip and cleft palate; severe reductive defects in both upper limbs and only syndactylia in the lower ones. Both sibs died soon after delivery. Autosomic recessive pattern of inheritance of this disorder, presentation in the same sibship of Roberts and SC-phocomelia syndromes, as different degrees of expression of the same disorder, and relationship of cytogenetic findings with cell division are discussed.