Polymorphism rs2073618 of the <i>TNFRSF11B</i> (<i>OPG</i>) Gene and Bone Mineral Density in Mexican Women with Rheumatoid Arthritis

Abstract

Osteoporosis (OP) is highly prevalent in rheumatoid arthritis (RA) and is influenced by genetic factors. Single-nucleotide polymorphism (SNP) rs2073618 in the <i>TNFRSF11B</i> osteoprotegerin (<i>OPG</i>) gene has been related to postmenopausal OP although, to date, no information has been described concerning whether this polymorphism is implied in abnormalities of bone mineral density (BMD) in RA. We evaluated, in a case-control study performed in Mexican-Mestizo women with RA, whether SNP rs2073618 in the <i>TNFRSF11B</i> gene is associated with a decrease in BMD. RA patients were classified as follows: (1) low BMD and (2) normal BMD. All patients were genotyped for the <i>rs2073618</i> polymorphism by PCR-RFLP. The frequency of low BMD was 74.4%. Higher age was observed in RA with low BMD versus normal BMD (62 and 54 years, resp.; <i>p</i> < 0.001). Worse functioning and lower BMI were observed in RA with low BMD (<i>p</i> = 0.003 and <i>p</i> = 0.002, resp.). We found similar genotype frequencies in RA with low BMD versus RA with normal BMD (GG genotype 71% versus 64.4%, GC 26% versus 33%, and CC 3% versus 2.2%, resp.; <i>p</i> = 0.6). We concluded that in Mexican-Mestizo female patients with RA, the rs2073618 polymorphism of the <i>TNRFS11B</i> gene is not associated with low BMD.