Case 2 is a 5-year 11-month-old girl, the first child of healthy non-consanguineous parents. She was born at 36 weeks of gestation by caesarean section because of intrauterine growth restriction. Birth weight was 1850 g (<10th centile) and head circumference 31 cm (<10th centile). She first walked independently at 22 months old and spoke her first words at 18 months. At 5 years and 11 months old, weight was 14.5 kg (<3rd centile), height 102.5 cm (<3rd centile) and OFC 47 cm (<2nd centile). She had troublesome gastro-oesophageal reflux and a high degree hypermetropia. On examination she had sparse hair, epicanthic folds and a wide mouth with thick lips. Bilateral clinodactyly of the fourth and fifth fingers with generalised joint laxity was noted. Brain MRI showed agenesis of the posterior third of the corpus callosum. CGH was reported as arr 2p25(5511851–16027633)x1(hg 19). The deletion encompassed the SOX11 and MYCN genes. The deletion was not present in either parent.
Case 3 is a 14-year-old girl, the first child of healthy non-consanguineous parents. She was born at 37 weeks of gestation. Birth weight was 2840 g (9th centile) and head circumference 33 cm (2nd centile). She had a weak suck and difficulty feeding in the neonatal period. She first walked at the age of 20 months. Her fine motor skills were impaired. She had no speech delay. At 14 years old, her height was 158 cm (50th) and head circumference was 52 cm (<2nd). She was dysmorphic with a high forehead, narrow palpebral fissures, a smooth philtrum, micrognathia and a high arched palate. A scoliosis, inverted nipples, bilateral fifth finger clinodactyly and 2–3 toe syndactyly were noted. CGH was reported as arr 2p25(5838893–7023548)(hg 19)x1. The deletion included SOX11, RSAD2 and CMPK2 genes. The deletion was not found in the mother. The father was not available for testing.