Expression of paralog APL1A is regulated by the transcription factor Rel2, the positive regulator of the Immune deficiency (Imd) immune pathway, while paralog APL1C is regulated by transcription factor Rel1, positive regulator of the Toll pathway [14, 16, 17, 39]. Here, TLR4 is linked to hyperinsulinemic hypoglycemia, familial, 4.