Defective SLC1A3 causes episodic ataxia 6 (EA6)

The SLC1 gene family includes five high-affinity glutamate transporters encoded by SLC1, 2, 3, 6 and 7. These transporters can mediate transport of L-Glutamate (L-Glu), L-Aspartate (L-Asp) and D-Aspartate (D-Asp) with cotransport of 3 Na+ ions and H+ and antiport of a K+ ion. This mechanism allows glutamate into cells against a concentration gradient. This is a crucial factor in the protection of neurons against glutamate excitotoxicity (the excitation of nerve cells to their death) in the CNS.

SLC1A3 is highly expressed in the cerebellum but also found in the frontal cortex, hippocampus and basal ganglia. Defects in SLC1A3 have been shown to cause episodic ataxia type 6 (EA6; MIM:612656) where mutations in SLC1A3 can lead to decreased glutamate uptake, thus contributing to neuronal hyperexcitability to cause seizures, hemiplegia and episodic ataxia (Jen et al. 2005, de Vries et al. 2009).