The encoded gene product is responsible for catabolism of gamma-aminobutyric acid (GABA), a mostly inhibitory neurotransmitter in the central nervous system, into succinic semialdehyde. Deficiency of this encoded protein includes psychomotor retardation, hypotonia, hyperreflexia, lethargy, refractory seizures, and EEG abnormalities. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2010]