Ghrelin gene polymorphisms in rheumatoid arthritis

Abstract

Objectives: Ghrelin, an endogenous orexigenic peptide, has anti-inflammatory effects, down-regulates pro-inflammatory cytokines, and its altered levels are reported in various inflammatory diseases. The human preproghrelin (ghrelin/obestatin) gene shows several single nucleotide polymorphisms (SNPs) including Arg51Gln, Leu72Met, Gln90Leu, and A-501C. The aim of this study was to investigate the frequency, and clinical significance, of these four SNPs in a small cohort of Turkish patients with rheumatoid arthritis (RA).

Methods: The study included 103 patients with RA and 103 healthy controls. In the RA group, disease activity and disease-related damage were assessed using the Disease Activity Score-28 (DAS-28), and the modified Larsen scoring (MLS) methods. In all the participants, genomic DNA was isolated and genotyped by polymerase chain reaction and restriction fragment length polymorphism analysis.

Results: The frequencies of ghrelin gene SNPs were 82.5 and 79.6% in the RA and control groups, respectively, and there were no significant differences in terms of genotype distributions and allele frequencies for these four SNPs between the groups. However, the A-501C SNP was found to be associated with early disease onset, and Gln90Leu SNP with less frequent rheumatoid factor positivity, in the RA group.

Conclusion: A-501C SNP is associated with earlier onset of RA suggesting that genetic variations in the ghrelin gene may have an impact on RA.