Since its discovery, genetic variations in the GRIN2B translating into GluN2B protein have consistently been linked to West syndrome, intellectual impairment with focal epilepsy, developmental delay, macrocephaly, corticogenesis, brain plasticity, as well as infantile spasms and Lennox–Gastaut syndrome [5,60,61,62,63]. The gene discussed is GRIN2B; the disease is focal epilepsy.