The clinical features of this disease include:
- Intellectual disability (severe to profound)
- Global developmental delay
- Failure to thrive
- Growth deficiency (although birth growth parameters are usually normal)
- Coarse facies
- Microcephaly
- Seizures (some patients)
- Brain imaging abnormalities:
- Ventriculomegaly
- Arachnoid cysts
- Brain atrophy
- Dysgenesis of corpus callosum
- T2/FLAIR signal abnormalities in the subcortical white matter
- Grey sclera
- Mongolian spots
- Strabismus
- Hypotonia