All individuals with a mutation in the SUCLA2 gene have these features (based on 29 patients; 20 males, 9 females):
- Onset birth-6 months.
- (Truncal) muscle hypotonia.
- Delayed motor development.
- Sensorineural hearing loss.
- Dystonia / Hyperkinesia.
Recognizable dysmorphisms:
- None.
Most individuals with a mutation in the SUCLA2 gene also have these features:
- Absent speech (but able to communicate via specially adapted electronic device).
- Feeding problems.
- Failure to thrive.
- Gastro-oesophageal reflux.
- Progressive spasticity.
- Progressive kyphosis/scoliosis.
- Ophthalmoplegia/strabismus/ptosis.
- Hyperhidrosis.
- Hypersalivation.
- Intestinal dysmotility with frequent vomiting / constipation.
- Basal ganglia lesions on MRI.
Other less frequently reported clinical features are:
- Epilepsy.
- Ataxia.
- Athetosis.
- Weak or absent deep tendon reflexes.
- Cerebral atrophy on MRI.
- Cerebellar atrophy on MRI.
Biochemical features of the SUCLA2 defect include:
- Elevated serum lactate.
- Elevated urinary lactate.
- Mildly elevated plasma methylmalonate.
- Mildly elevated urinary methylmalonate.
- Elevated plasma/blood C4-dicarboxylic carnitine.
A comprehensive spectrum of clinical characteristics observed in patients with SUCLA2-related syndrome is available on the Graph and Charts page.
Prognosis
Life span varies greatly, from few weeks to >25 years. Mean age in 16 Faroese individuals 8 years; 10 months.