IL6 and obesity due to melanocortin 4 receptor deficiency: The relationship between the –174 G > C SNP appears to be complex in that while the –174 C allele appears to be the risk allele associated with obesity [21], it is the –174 G allele that is associated with raised serum lipids concentrations [87,92,93], despite the –174 C allele being shown to be associated with raised IL-6 and CRP levels [21,91,114,115].