HNF4A and diabetes mellitus: <h4>Objective</h4>To present the case of an atypical Hepatocyte Nuclear Factor 4 Alpha <i>(HNF4A)</i> mutation that is not consistent with the classically published presentation of <i>HNF4A</i>-Mature Onset Diabetes of the Young (MODY).<h4>Methods</h4>Clinical presentation and literature review.<h4>Results</h4>A 43-year-old nonobese man was referred to the endocrinology clinic for evaluation of elevated fasting blood glucose (FBG) measurements.