SLC4A4 and familial or sporadic hemiplegic migraine: SLC1A3 (encoding the glial glutamate transporter EAAT1) and SLC4A4 (encoding the electrogenic sodium bicarbonate cotransporter NBCe1) have been proposed as potential fourth and fifth genes (FHM4 and FHM5) responsible for pure hemiplegic migraine [52, 56].