The SLC6A1 gene

SLC6A1 is a gene found on chromosome 3 that encodes a protein called GAT-1 (gamma-aminobutyric acid transporter, or GABA, type 1).

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Gamma-aminobutyric acid (GABA) is a neurotransmitter, i.e. a chemical that allows nerve cells in the brain to communicate with each other. GABA slows down or “brakes” the activity of neurons and is the main neurotransmitter that inhibits the central nervous system.

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GABA is released from nerve endings in response to an electrical impulse, crosses the synapse (the space between two neurons) and binds to receptors on the surface of the receiving neuron. This binding blocks the electrical activity of the neuron, reducing the possibility of a new signal being transmitted. After performing its function, GABA is rapidly removed from the synaptic space, mainly through the action of transporters such as GAT-1.

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The task of GAT-1 is therefore to remove gamma-aminobutyric acid from the synaptic cleft and transport it to presynaptic neurons (where GABA can be recycled) and astrocytes (where GABA can be broken down). GAT-1 therefore serves to ‘recapture’ GABA once it has performed its function.

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A mutation in the SLC6A1 gene can cause the production of a GAT-1 protein that does not function properly. The neurological disorders of people with a SLC6A1 mutation are due to the malfunctioning of GAT-1.

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Common symptoms include epilepsy, mental delay, behavioural problems, sleep disorders and autism.