Since the levels of MAFA and MAFB are more sensitive to metabolic stressors in relation of other islet-enriched TFs (34), we propose that compromised MAF expression upon exposure to obesity- and insulin resistance–induced effectors leads to β cell dysfunction and reduced cell identity due to induction of GAST+ cell–associated gene products. Here, MAFB is linked to obesity due to melanocortin 4 receptor deficiency.