Serum miR-122 levels were significantly lower in HNF1A-DM patients [0.046 (0.023, 0.121)] than in T2DM patients [0.165 (0.036, 0.939), P = 0.02] and healthy controls [0.249 (0.049, 1.234), P = 0.019]. The gene discussed is HNF1A; the disease is type 2 diabetes mellitus.