The clinical features of this disease may include followings with imaging and supportive laboratory findings:
Neurologic findings
- Progressive loss of developmental milestones, typically beginning between ages three and seven months
- Spasticity
- Impaired speech
Ophthalmologic features
- Optic atrophy
- Loss of eye contact
- Nystagmus
- Visual impairment
Brain MRI findings
- Diffuse bilateral symmetric signal abnormality in cerebral white matter
- In some cases, signal abnormalities in the corpus callosum, internal capsule, midbrain, middle cerebellar peduncles, and cervical spinal cord
Supportive laboratory findings
- Biochemical Analysis
- Increased CSF glycine, glutamate, and lactate
- Fibroblasts show decreased mitochondrial complex I and II activity
- Mildly decreased complex IV activity
- Decreased mtDNA levels
- Decreased mitochondrial membrane potential
- Decreased oxidative phosphorylation and ATP production
- Respiratory chain enzyme analysis on muscle tissue reveals deficient activity of complex II and IV