MTNR1B and gestational diabetes: Five of the most identified genes in GDM are: (1) Transcription factor 7-like 2 [TCFL7L2] [80,81]; (2) Melatonin receptor 1B [MTNR1B] [82,83]; (3) CDK5 regulatory subunit-associated protein 1-like 1 [CDKAL1] [84,85]; (4) Potassium voltage-gated channel, KQT-like subfamily, member 1 [KCNQ1] [86,87]; and (5) Insulin receptor substrate-1 [IRS1] [88,89].