In RECENT years, the relationship between congenital malformations and chromosomal abnormalities has been well established. The present paper describes a mentally retarded girl with multiple congenital anomalies and a 1/G translocation. In addition, five members of the kindred in three consecutive generations had an abnormal G chromosome. Report of Case A 5-year-old white girl was brought to our attention in August 1965 because of somatic and mental retardation. She was the product of a full-term gestation, weighing 8 lb 5 oz (3.8 kg). During the mother's pregnancy, occasional bleeding, infection of the external genitalia, and anemia were observed. The rest of the child's history was uneventful except for pneumonia at the age of 1 month and chronic asthma. Physical examination revealed a slightly somatically retarded child (Fig 1) weighing 36 lb 4 oz (16.4 kg), within the sixth percentile, and with a height of 39½ inches (100.3 cm), below the