Editor—Simpson-Golabi-Behmel syndrome (SGBS, MIM 312870) is an X linked condition characterised by pre- and postnatal overgrowth, coarse facial appearance, large mouth, predisposition to embryonic neoplasia,1 and a variety of visceral and skeletal abnormalities. Psychomotor development in the syndrome is extremely variable, ranging from normal intelligence,2 to moderate impairment, to severe impairment evident from birth.3 4 We report the cases of two male sibs with normal psychomotor development, diagnosed at 6 and 7 years of age with SGBS, who manifest significant behavioural disturbances consistent with a diagnosis of attention deficit hyperactivity disorder (ADHD). This is the first report of an association between SGBS and a specific behavioural phenotype (ADHD).

Case 1, the older of the two boys, was the first born to non-consanguineous, healthy, white parents. The pregnancy was complicated at 36 weeks by polyhydramnios and pregnancy induced hypertension. An ultrasound performed at this time discovered a left sided diaphragmatic hernia. No other fetal abnormalities were reported. Labour was induced at 39 weeks and the child was delivered by forceps assisted vaginal delivery. Birth weight was 4400 g (well above the 97th centile) and immediate transfer for stabilisation and surgical repair of the diaphragmatic hernia was undertaken. Other birth indices were not recorded. The primary surgical repair was successful but was complicated by a left pneumothorax on day 4 of life. This complication was successfully managed and the subsequent postsurgical course was uneventful. The child was discharged from hospital aged 14 days.

At 5 months bilateral inguinal hernias were noted and surgically repaired. From 6 months onwards the child was noted to be extremely unsettled, seldom sleeping for more than two hours at a time. From 10 months onwards he began to wake screaming several times a night. His behaviour became increasingly unpredictable and aggressive over …