The clinical features of this disease, per organ system, include:
Central Nervous System
- Encephalopathy
- Hypotonia
- Cerebral atrophy
- Thin corpus callosum
- Delayed myelination
- Leukodystrophy
- White matter abnormalities
- Brainstem and basal ganglia lesions (some patients)
- Seizures (some patients)
- Ataxia (some patients)
- Dystonia, choreoathetosis (some patients)
- Swallowing dysfunction
- Stroke-like episodes
Head and Neck
- Microcephaly (some patients)
- Plagiocephaly (some patients)
- Opthalmological and hearing defects (uncommon), including:
- Strabismus
- Cataracts
- Nystagmus
- Optic atrophy
- Reduced vision
- Sensorineural hearing impairment
- Dysmorphic facial features (some patients), including:
- Epicanthus
- Downslanting palpebral fissures
- Upslanting palpebral fissures
- Saddle nose
- Dolichocephaly
- Elongated face
- Everted lower lip
- Thick eyebrows
Skeletal
- Scoliosis (some patients)
- Small feet (some patients)
Cardiovascular (uncommon)
- Hypertrophic cardio myopathy
- Arrythmia
- Pulmonary hypertension
- Congenital heart disease
Gastrointestinal
- Gastroesophageal reflux
- Dysphagia
- Gastrointestinal dysmotility
Genitourinary
- Renal tubular acidosis (some patients)
- Hypospadias
Immune system
- Recurrent infections (some patients)
- Neutropenia (some patients)
Other(s)/Abnormal lab findings
- Increased serum alanine
- Increased serum ammonia
- Increased serum lactate
- Mitochondrial respiratory chain defects (in muscles and fibroblasts)
- Depletion of mitochondrial DNA
- Abnormal liver enzymes
- Lactic Acidosis
- Global developmental delay
- Failure to thrive
- Low birth weight
The onset is usually at birth or early infancy.