Roberts syndrome and SC phocomelia syndrome are an autosomal recessive condition of prenatal and postnatal growth retardation, symmetrical limb reduction, and craniofacial abnormalities. A distinction has been made between the two syndromes on the basis of relative severity of these manifestations. Where chromosome studies have been carried out, most have been reported as normal. However, there have been two reports of consistent centromere abnormalities; one in a patient with SC phocomelia (pseudothalidomide syndrome), the other in a patient with Roberts syndrome. Four patients with similar phenotypic manifestations have recently been shown in our laboratory to have the same centromere puffing and splitting. These four patients had other clinical manifestations in common, including bilateral corneal opacities, microcephaly, absence of radii, limited extension at knees and elbows, apparent enlargement of the phallus, and survival beyond the neonatal period.