Significance of SAA1 gene polymorphism in the development of AA amyloidosis in patients with rheumatoid arthritis in the Moscow population

Abstract

Objective: to estimate the significance of SAA1 gene polymorphism in the development of AA amyloidosis in patients with rheumatoid arthritis (RA) in the Moscow population. Subjects and methods. The investigation included 57 RA patients treated at the clinic of the Research Institute of Rheumatology, Russian Academy of Medical Sciences, for histologically verified AA amyloidosis. In 41 of them, polymorphism of exon 3 of the SAA1 gene (SNP rs1136747 c.224T→C and SNPrs1136743 c.209C→T) was studied by polymerase chain reaction and restriction fragment length polymorphism analysis. Results. The carriage of the а/а genotype increases the likelihood of AA amyloidosis by 3 times in patients with RA (odds ratio (OR) = 3.0; p = 0.007). At the same time, the presence of allele β in the α/β genotype epistatically suppresses the action of allele α, by showing a 3-fold reduction in the risk of secondary amyloidosis in RA patients who were carriers of this genotype. Conclusion. The а/а genotype at the SAA1 locus is a risk factor for AA amyloidosis in patients with RA in the Moscow population; at the same time its presence of allele β in the heterozygous or homozygous state is a factor for preventing the development of this complication.