| Severe intellectual disability | IQ typically below 40 |
| Dystonia | progressive movement disorder, often beginning in childhood |
| Ataxia | impaired coordination |
| Hypotonia | decreased muscle tone in infancy |
| Seizures | observed in approximately 30% of patients |
| Speech impairment | most patients remain non-verbal |
| Microcephaly | small head circumference |
| Facial dysmorphism | including elongated face, prominent ears, and nasal abnormalities |
| Skeletal abnormalities | including kyphosis and joint contractures |
| Databases | OMIMOrphanetClinicalTrialsPubMed |