INSIG2 and obesity due to melanocortin 4 receptor deficiency: Although sequence variation at the INSIG2 locus that could lead to differences in the level of INSIG2 between individuals might plausibly contribute to variation in risk for obesity, we report here that there was no increased susceptibility for homozygous carriers of the rs7566605 minor C allele in an ethnically and racially diverse sample of 24,722 individuals belonging to four cohorts.