LCN2 and obesity due to melanocortin 4 receptor deficiency: Among differentially expressed genes irrespective of obesity and glucose intolerance states, we identified a nonsense mutation, c.409C > T (p.Gln137X), in the lipocalin 2 (Lcn2) gene which encodes a secreted protein called neutrophil gelatinase-associated lipocalin, a well-known biomarker for inflammation.