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 5 is a 34-year-old man, the third child of healthy non-consanguineous parents (patient 16 from the study of De Rocker et al). He was born at term. Birth weight was 3750 g (75th). He had intellectual disability, speech delay and epilepsy. On examination at age 34 years, height was 150 cm (3rd centile) and head circumference 53 cm (3rd centile, corrected for height). He had facial dysmorphism: microretrognathia, short philtrum and mild trigonocephaly. Scoliosis and cryptorchidism were also noted. CGH was reported as arr 2p25(2231163–8300707)(hg 19)x1 with deletion of the SOX11 and MYT1L genes. This was paternally inherited; a detailed phenotypic description of the father was not available, but he was reported to be epileptic and had intellectual disability and speech delay.