Summarised view of clinical features in our cohort as well as in the previously published reports
| Our patients | Previous reports1–4 | Total | |
| Gender | 22 M/23 F (0.96) | 12 M/9 F/9 NR | 1.06 |
| Inheritance | 3 dn/31 inherited 20 mat/11 pat | 2 dn/18 inherited 15 mat/3 pat | 89.8% inherited (71.4% mat, 28.6% pat) |
| Parent’s phenotype when inherited | 7 affected/16 unaffected/7 NR | 3 affected/3 unaffected/10 NR | 10 affected/19 unaffected/17 NR |
| Perinatal data | |||
| Hypotonia | 5/21 (24%) | 0/10 | 5/31 (16%) |
| Feeding difficulties | 5/17 (29%) | 1/1 | 6/18 (33%) |
| Neurodevelopmental features | |||
| Motor delay | 19/39 (49%) | 5/14 | 24/53 (45%) |
| Speech delay | 35/40 (88%) | 14/20 | 51/62 (82%) |
| Learning disabilities/ID | 30/35 (86%) | 14/17 | 44/52 (85%) |
| ASD | 24/36 (67%) | 14/21 | 38/57 (67%) |
| Seizures | 10/29 (34%) | 1/11 | 11/40 (28%) |
| Malformations | |||
| Abnormal brain MRI | 7/24 (29%) (3 cases of myelination delay) | 1/9 | 8/33 (24%) |
| Cardiac malfomations | 4/15 (27%) | 2/11 | 6/26 (23%) |
ASD, autism spectrum disorder; dn, de novo; ID, intellectual deficiency; mat, maternally inherited; NR, not reported; pat, paternally inherited.