Fatima and coworkers [136] reported that for both maternal serum at the 28th week of gestation and at 6 weeks postpartum, the irisin levels of GDM mothers were significantly lower than for the non-GDM cohort (GDM: 42.1 ± 3.2 pg/mL and non-GDM: 72.9 ± 9.1 pg/mL, respectively, and GDM: 138.3 ± 6.8 pg/mL and non-GDM: 265.0 ± 40.9 pg/mL, respectively). The gene discussed is FNDC5; the disease is gestational diabetes.