Our group has previously shown that a common CNR1 haplotype (15% frequency in subjects of Northern European ancestry) is associated with elevated fasting TG levels and reduced levels of HDL-C in one of the most rigorously phenotyped family-based obesity cohorts in the U.S. Again, this effect was partly independent of BMI [4]. Here, CNR1 is linked to obesity due to melanocortin 4 receptor deficiency.