NR1H2 and obesity due to melanocortin 4 receptor deficiency: Single nucleotide polymorphisms (SNP) of the NR1H3 (LXRalpha) and NR1H2 (LXRbeta) genes have recently been associated with many metabolic indicators and conditions, including circulating total, LDL and HDL (High Density Lipoprotein)-cholesterol levels for NR1H3 [18-20], and type 2 diabetes mellitus and obesity for both NR1H3 and NR1H2 [21-24].