These controversial data have been the starting point for contradicting interpretations of recent meta-analyses, ranging from no increase in the risk for the hospitalization of HF after DPP-4 inhibitor use (Savarese et al., 2016) to an increased risk (Kongwatcharapong et al., 2016), indicating that there are considerable differences between substances within the class of DPP-4 inhibitors. The gene discussed is DPP4; the disease is hydrops fetalis.