SLC6A1 and early-onset autosomal dominant Alzheimer disease: With regard to GAT1’s function in GABA regulation, abnormal hGAT1 neurotransmission has been associated with low GABA levels in the synaptic cleft, which may implicate several neurological disorders such as Alzheimer’s disease [5], schizophrenia [6,7], Parkinson’s disease [8], and epilepsy [9].