Four single nucleotide polymorphisms (SNPs) (rs2237892, rs2237895, rs2237897, and rs2283228) in KCNQ1 are reported to be associated with type 2 diabetes mellitus (T2DM), possibly caused by a reduction in insulin secretion and higher fasting glucose, but the results are inconsistent. Here, KCNQ1 is linked to diabetes mellitus.