Dopamine transporter is a membrane-spanning protein that binds the neurotransmitter dopamine; DAT provides the primary mechanism through which dopamine is cleared from synapses, transporting dopamine from the synapse into a neuron. DAT is present in the peri-synaptic area of dopaminergic neurons in areas of the brain where dopamine signaling is common. DAT is implicated in a number of dopamine-related disorders, including attention deficit hyperactivity disorder, bipolar disorder, clinical depression, and alcoholism. DAT is located on human chromosome 5, consists of 15 coding exons, and is roughly 64 kbp long. Evidence for the associations between DAT and dopamine related disorders has come from a genetic polymorphism in the DAT, which influences the amount of protein expressed.