Case 7 is a 2-year-old girl, the first child of healthy non-consanguineous parents. She was born at 39 weeks of gestation by elective caesarean section. Birth weight was 3.5 kg (50th). There were feeding difficulties and poor weight gain in the first month of life. This resulted in hospital admission. Gastro-oesophageal reflux was diagnosed and the feeding difficulties resolved with gaviscon. At this time generalised hypotonia was noted. There was a history of mild gross motor delay; she first sat independently at 10 months and walked at 15 months. At the age of 2 years, she had begun to run. There were no concerns relating to fine motor skills. There was mild speech delay; at the age of 2 years, she was not producing two word phrases. She was physically well. On examination her head circumference was 47 cm (50th centile) and weight 10 kg (2nd centile). She had deep set eyes, full cheeks and thick lips. There was sparse scalp hair. She had bilateral fifth finger clinodactyly and hypoplasia of the nails of the fifth fingers and toes. CGH was reported as arr2p25.2(5166592–6400126)(hg19)x1. Only the SOX11 gene was deleted, and it was not possible to test parental samples.
Case 4 is a 25-year-old woman, the third child of healthy non-consanguineous parents. Pregnancy was complicated by reduced fetal movements. Birth weight was 3130 g (25th centile). Choanal stenosis and persistent ductus arteriosus were present in the neonatal period. She first walked at 4 years and spoke at 3 years old. At the age of 25 years old, her height was 162 cm (25th centile), weight 50 kg (10th centile) and head circumference 49 cm (<0.4th centile). She has severe intellectual disability and aggressive behaviour. She is physically well but has hypermetropia. She has a flat face with upslanting palpebral fissures and wide mouth with thick lips. Short second fingers with bilateral fifth finger clinodactyly was present along with skin syndactyly of toes 2–3 and 4–5. CGH was reported as arr 2p25(5535091–16398225)(hg 19)x1 with deletion of SOX11 and MYCN. The deletion was not found in either parent.