Genome-wide association studies have disclosed chromosomic regions containing DM susceptibility genes in chromosome 10q, which were later ascribed to intronic variations in the transcription factor 7-like 2 (TCF7L2) gene and TCF7L2 variants have been consistently associated with type 2 diabetes (T2D) in different populations [3], including the Brazilian population [4]. Here, TCF7L2 is linked to type 2 diabetes mellitus.