A standard AHC diagnosis was confirmed by the ATPA3 gene variant in the twins (Family 1: Case 1 and Case 2) but, not in siblings (Family 2) that carried a variant in GRIN2A gene in the younger brother (Case 3) and an unreported variants for AHC in GRIN2A, SCN1B, and KCNQ2 genes in the older brother (Case 4). This evidence concerns the gene GRIN2A and alternating hemiplegia of childhood.