Population-based studies have revealed multiple single-nucleotide polymorphisms in the vasopressin gene pathway (AVP, AVPr1a, and AVPr1b genes) that are associated with hyperglycemia, insulin resistance, elevated body mass, and diabetes mellitus.9,24,25 Vasopressin is difficult to measure in blood samples because of its low concentration, small size, and rapid degradation. Here, AVP is linked to diabetes mellitus.