HACL2 and gestational diabetes: Our study identified 15 novel CpG sites annotated to 10 unique genes, including TNXB, EPPK1, ILVBL, B3GNTL1, IL18, XRCC3, C20orf3. Hypomethylation of TNXB gene and differential expression of EPPK1 protein in the placenta has been reported to be associated with GDM [45, 46].