Of 8 top candidate genes for schizophrenia affected by CNVs (Luo et al., 2014), only B-cell CLL/lymphoma 9 (BCL9) (1q21.1), which is required in the Wnt signaling pathway, was reported to be associated with T2DM (Anderson et al., 2015) or schizophrenia (Li et al., 2011), although there are not enough studies on the relationship between CNVs and T2DM, unlike schizophrenia. Here, BCL9 is linked to type 2 diabetes mellitus.