SMAD7 and type 2 diabetes mellitus: In T2DM, an intronic variant IVS2‐21 C > T of SMAD7 is associated with the disease under the recessive genetic model.50 Merriman et al suggested an association between chromosome 18q12‐q21 region (SMAD7 locates) with T1DM in 882 families,51 and Barrett et al confirmed the association between rs12953717, a tag SNP (P = 10−6) for SMAD7, and T1DM in a genome‐wide association study among Caucasians.52 Furthermore, a study involving 928 T1DM patients and 922 control patients revealed that three genes, including SMAD7, were down‐regulated in T1DM patients.53