The gamma-aminobutyric acid (GABA) A receptor is a multisubunit chloride channel that mediates the fastest inhibitory synaptic transmission in the central nervous system. This gene encodes the theta subunit of the GABA A receptor. The gene is mapped to chromosome Xq28 in a cluster of genes including those that encode the alpha 3 and epsilon subunits of the GABA A receptor. This gene location is also the candidate region of two different neurologic diseases: early-onset parkinsonism (Waisman syndrome) and X-linked mental retardation (MRX3). [provided by RefSeq, Nov 2009].