SLC4A4 - In two patients with proximal renal tubular acidosis and a homozygous frameshift mutation S982NfsX4 in SLC4A4, which encodes for a sodium bicarbonate cotransporter NBCe1, hemiplegic migraine was reported, while some heterozygous carriers reported common forms of migraine [61]. The gene discussed is SLC4A4; the disease is familial or sporadic hemiplegic migraine.