Most often, MODY is caused by LOF variants in the coding regions of TF genes, but it can also be due to LOF variants in the cis-regulatory elements (CREs) of these genes, as has been shown, for example, for HNF1A (Gragnoli et al., 1997) and HNF4A (Hansen et al., 2002). Here, HNF1A is linked to MODY.