Genome-wide association studies have found an obesity-related single-nucleotide polymorphism rs10938397 near the glucosamine-6-phosphate deaminase 2 gene (GNPDA2) encoding, an enzyme that catalyzes the deamination of the glucosamine-6-phosphate involved in the hexosamine signaling pathway, but the molecular mechanisms underlying the missing link between GNPDA2 and obesity remain elusive. The gene discussed is GNPDA2; the disease is obesity due to melanocortin 4 receptor deficiency.