Abstract
OBJECTIVE: To evaluate the effect of serum amyloid A (SAA) 1 and SAA2 gene polymorphisms on SAA levels and renal amyloidosis in Turkish patients with familial Mediterranean fever (FMF). METHODS: SAA1 and SAA2 gene polymorphisms and SAA levels were determined in 74 patients with FMF (39 female, 35 male; median age 11.5 yrs, range 1.0-23.0). All patients were on colchicine therapy. SAA1 and SAA2 gene polymorphisms were analyzed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). SAA and C-reactive protein (CRP) values were measured and SAA/CRP values were calculated. RESULTS: The median SAA level was 75 ng/ml (range 10.2-1500). SAA1 gene polymorphisms were: a/a genotype in 23 patients (31.1%), a/beta genotype in 30 patients (40.5%), a/g genotype in one patient (1.4 %), beta/beta genotype in 14 patients (18.9%), beta/g genotype in 5 patients (6.8 %), and g/g genotype in one patient (1.4%). Of the 23 patients who had a/a genotype for the SAA1 polymorphism, 7 patients had developed renal amyloidosis (30.4%) compared to only one patient without this genotype (1/51; 2.0%); p < 0.001. SAA2 had no effect on renal amyloidosis. SAA1 and SAA2 genotypes had no significant effect on SAA levels. SAA/CRP values were significantly lower in patients with the SAA1a/a genotype, compared to other SAA1 genotypes: 0.16 (0.025-1.96) versus 0.23 (0.012-28.20), p < 0.05. CONCLUSION: SAA1a/a genotype is one genetic factor that confers a significant risk for amyloidosis in the Turkish FMF population. Neither the SAA1 nor SAA2 genotypes had a significant effect on SAA level.
