POMC and infantile spasms: Why does infantile epileptic spasms syndrome (IESS) occur with a variety of underlying conditions and why does it respond to adrenocorticotrophin hormone (ACTH)/corticosteroids? Our scoping review summarizes five hypotheses from the literature: gene/epigenetic regulation, stress/HPA axis activation, neuroinflammation/immune function, altered neuronal transmission, and metabolic dysfunction.