Genetic Risk Factors of Amyloidogenesis in Familial Mediterranean Fever

Abstract

Background/Aims: Evaluation of the risk factors, and phenotype-genotype correlation of familial Mediterranean fever (FMF) gene (MEFV) and serum amyloid A1 (SAA1) gene polymorphisms in renal amyloidosis. Methods: We investigated MEFV and SAA1 genotypes (α, β, and γ isoforms) in 50 FMF patients and 50 healthy children. Tel-Hashomer criteria were used for the diagnosis and severity scoring of FMF. Results: The most common MEFV mutation and SAA1 genotype were M694V/M694V (n = 26/50) and SAA1 α/α (n = 26/50), respectively. Positive family history for amyloidosis was significantly higher (p < 0.001) with more severe clinical course (p = 0.006) in the amyloidosis group than the non-amyloid group. In M694V/M694V mutation, erysipelas-like skin erythema (p = 0.029), arthritis (p = 0.004), arthralgia (p < 0.001) were significantly more frequent with higher severity scores (p = 0.008) than the patients with other mutations. Comparison of the SAA1 α/α genotype with other genotypes revealed more frequent arthritis (p = 0.003) in the SAA1 α/α genotype. In amyloidosis group patients having both M694V/M694V and SAA1 α/α genotypes were the largest subgroup (n = 14, p < 0.001). Logistic regression analysis for amyloidosis corrected risk revealed a 1.2 times increase in M694V/ M694V, a 2.4 times increase in SAA1 α/α genotypes and a 2.5 times increase when both are together. Conclusion: Positive family history for amyloidosis and presence of SAA1 α/α genotype in M694V/M694V mutation may predispose to amyloidosis by increasing the clinical severity. Therefore, in such children early colchicine treatment might be recommended even if they are asymptomatic. Copyright © 2005 S. Karger AG.