4-hydroxybutyricaciduria
succinic semialdehyde dehydrogenase deficiency
A rare (±350 families in the world literature) autosomal recessive condition (OMIM:271980) characterised by a defect in metabolism of the neurotransmitter 4-aminobutyric acid (GABA), resulting in an accumulation of GHB, a compound with numerous neuromodulatory properties.Clinical findings
Most common in consanguineous pedigrees; delays in intellectual, motor, speech and language milestones; ocular problems, including strabismus, nystagmus, retinitis and oculomotor apraxia; also, hypotonia, hyporreflexia, seizures, nonprogressive ataxia, hyperkinesis, hyperreflexia, autism, myopathy and choreoathetosis.
Imaging
T2-weighted signal defects of the globus pallidus (bilaterally and symmetrically), brainstem and cerebellar dentate nucleus; presence of subcortical white matter, attributed to oedema or an inflammation.
Molecular pathology
Mutation of ALDH5A1 on chromosome 6p22.