About 26% of the heterozygous males and 40% of the homozygous males developed the obese phenotype (Figure 6A) (P < 0.05 and P = 0.01, respectively), which indicated that the Lc3 synthase gene B3gnt5 probably was one of factors that controlled for lack of obesity. The gene discussed is B3GNT5; the disease is obesity due to melanocortin 4 receptor deficiency.