Comnplete or partial duplication of 16q has been described in 20 cases. ' We have recently diagnosed a further three patients.Case I was delivered by Caesarean section at 32 weeks' gestation because of intrauterine growth retardation (< 3rd centile), oligohydramnios, and fetal distress. Dysmorphic features included a high forehead, beaked nose, long philtrum, micrognathia, simple ears, a simian crease on the right hand, anteriorly placed anus, and micropenis. The infant died on day 18. Necropsy findings were: head circumference 29 cm, crown-heel length 42 cm, absent fontanelles, hydrocephalus with aqueduct stenosis, bicuspid aortic and pulmonary valves, patent ductus arteriosus, anomalous origin of the left subclavian artery, absent gall bladder, and hydrocephalus secondary to aqueduct stenosis. Chromosome analysis showed a paternally derived unbalanced 10;16 translocation: 46,XY, -10, + der(10),t(10;16) (q26.3;q21)pat (figure).Case 2 was born to a 29 year old mother with one previous normal child and four first trimester miscarriages. Birth weight was 1800 g and head circumference 31 cm at 38 weeks' gestation. Low set ears, choroidal coloboma, transposition of the great arteries, ventricular septal defect, arthrogryposis, and hypospadias were apparent. He died at 3 months of age. Chromosome analysis showed a matemally derived unbalanced 3;16 translocation: 46,XY, -3, + der(3),t(3;16) (p26;q23)mat (figure). Parental translocations have most frequently involved chromosomes 9 (n = 3), 11 (n = 2), 15 (n =4), 18 (n = 2), and 22 (n = 2).Y4 Chromosomes 3 (case 2) and 10 (case 1) have not been reported previously. Francke5 described a patient with an unbalanced 16;22 translocation with duplication of the distal third of 16q and partial 22q monosomy. Her patient, who had more extensive 16q duplication than case 3, had intrauterine growth retardation, prominent forehead, generalised hypotonia, and a large patent ductus arteriosus, and died during the first year of life.
