| Feature | Proportion of Persons w/Feature | Comment |
|---|---|---|
| Developmental delay / Intellectual Disability | 35/35 | Generally mild-to-moderate, w/language development most affected domain |
| Dysmorphic facial features | 29/36 | Round face & short, broad nasal tip |
| Behavioral issues | 27/36 | |
| Hypotonia | 22/36 | Generally mild |
| Brain MRI abnormalities | 11/20 | Nonspecific |
| Musculoskeletal findings | 15/36 | Kyphoscoliosis, loose joints, hernia |
| Difficulty feeding | 14/36 | From infancy to childhood |
| Postnatal short stature | 14/36 | Generally 2-3 SD below mean |
| Difficulty gaining weight | 13/36 | |
| Sleep issues | 13/36 | Disrupted circadian rhythm |
| Microcephaly / smaller head (absolute or relative) | 12/36 | |
| Seizures | 11/36 | No specific type |
| Ataxia / gait difficulties / poor coordination | 9/36 |
From Reference (1) below