HNF1A and maturity-onset diabetes of the young type 3: We next performed a targeted qPCR screen to evaluate the expression levels of these candidate genes following the OE of WT-HNF1A or two HNF1A mutants that cause MODY3–H126D [5] and P291fsInsC [9, 35] in HEK293AD cells (Fig. S3A, B).