Study on the influence of polymorphisms of SAA1 and SAA2 gene on the development of AA-amyloidosis.

点击翻译按钮获取中文摘要

To examine whether polymorphism at the SAA loci is associated with the development of AA-amyloidosis, we determined the genotypes at the SAA1 and SAA2 loci in 43 AA-amyloidosis patients (amyloidosis population) and 77 patients with rheumatoid arthritis who had been ill for less than 5 years (early RA population). We also compared the frequencies of the genotypes at the SAA1 locus among 90 Korean, 95 Taiwanese and 103 Japanese healthy subjects. The frequencies of the γ/γ genotype and γ alleles at the SAA1 locus were significantly higher in the amyloidosis population than in the early RA population (34.9% versus 7.8% and 58.1% versus 33.8%, c2 test p=0.0001). The frequencies of the γ allele at the SAA1 locus in Koreans, Taiwanese and Japanese were 41.6%, 35.6% and 37.4%, respectively. The length of the latent period of AA-amyloidosis was significantly longer in the patients with smaller numbers of the γ allele at SAA1 locus (Spearman's correlation coefficient : -0.42 ; p<0.05). On the other hand, the mean CRP level during 2 years prior to the diagnosis of AA-amyloidosis was significantly higher in the patiesnts with larger numbers of the γ allele at the SAA1 locus (Spearman's correlation coefficient : 0.34 ; p<0.05). No significant association was found between amyloidosis and polymorphism at the SAA2 locus. We postulate that the allele SAA1 γ renders an RA patient susceptible to amyloidosis, possibly by affecting the severity of inflammation in RA.