We report the case of a patient who suffers from hypotransferrinemia due to a genetic defect, subsequently suffers organ damage due to non-transferrin bound iron (NTBI) and develops a paradoxical reaction of glucose metabolism as a result of treatment with corticosteroids. To our knowledge, this is the first description of such an effect in the medical literature. The mechanism and further course of this phenomenon are currently still in the dark. Due to its peculiarity, we therefore publish only the clinical key data for the time being. We reported earlier about the same patient’s change in his narcolepsy symptoms.