Genetic mutations in genes encoding Cl− channels (e.g., CLCN1, CLCN2, CLCN3, CLCN4, CLCN6) and transporters (e.g., KCC2) have been directly implicated in various forms of epilepsy, including severe early-onset forms like infantile migrating focal seizures. The gene discussed is SLC12A5; the disease is epilepsy.