For the STX1A variant p.(Gln226Arg) in an individual with West syndrome and Lennox-Gastaut syndrome, the homologous residue directly adjacent is affected in STX1B: p.(Gly226Arg) by a de novo variant in an individual with yet another developmental and epileptic encephalopathy with myoclonic-atonic epilepsy [41]. The gene discussed is STX1A; the disease is developmental and epileptic encephalopathy.