However, Berbari et al. analyzed the leptin response in pre-obese, obese, and food-restricted mice after generating inducible Ift88 and Bbs4 KOs [82] and found that the mutant mice showed leptin resistance only under obesity-inducing conditions, strongly indicating that leptin resistance is a secondary consequence of obesity. This evidence concerns the gene BBS4 and obesity due to melanocortin 4 receptor deficiency.