PAX4 and type 2 diabetes mellitus: Downregulated genes PAX4 and SLC2A2 and upregulated genes APOE each have evidence of a strong or causal role in T2D at the genetic level, while CYTIP was upregulated in T2D islets and has intron variant SNPs associated with T2D (e.g. rs13384965) (Forgetta et al., 2022; Figure 1H).