A newborn infant girl died at 1 day and was found to have severe intrauterine growth retardation, microcephaly, cleft lip and palate, single umbilical artery, absent thumbs, bicuspid pulmonic valve, pulmonary hypoplasia, malrotation of large and small bowel, and a 46,XX,13q+ chromosome constitution derived from a paternal t(4;13)(q25;q32) with resulting del(13q) and dup(4q). The paternal grandmother and great-grandmother also carried the balanced translocation. Each had had a child with multiple congenital anomalies including "duplex" thumbs. However, a chromosome analysis was not performed on these abnormal infants. Our patient's clinical and cytogenetic manifestations are discussed in relation to the Niebuhr map of chromosome 13.