GPNMB and obesity due to melanocortin 4 receptor deficiency: These data may suggest a gender-specific role of GPNMB; however, because female mice are relatively resistant against diet-induced obesity (Fig. 2A and Fig. S1A), careful consideration is required, and these results may suggest that the protective role of GPNMB against obesity-related metabolic disorders might be significant in considerably obese condition but not in mild obese condition.