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Previously reported studies concerning the effect of homozygosity of the 1.1 allele of the SAA gene found a correlation between this haplotype and susceptibility to amyloidosis in FMF patients. Another report revealed a strong association between SAA1 -13T/C and secondary amyloidosis in the rheumatoid arthritis patient group. In this study, we aimed to determine the effect of SAA1 -13T/C in FMF patients with and without amyloidosis. The study cohort, consisting of 166 patients with FMF was divided into two groups, according to the presence (n=66) or absence (n=100) of renal amyloidosis at study entry. MEFV gene mutation analysis and allelic variant of SAA1 gene -13 T/C was analyzed according to the previously described techniques. SAA1 -13 T allele frequencies were 0.5816, 0.23 and 0.4242 in controls, FMF patients and FMF-amyloidosis patients respectively. The difference between controls vs. FMF patients and FMF-amyloidosis patients were 0.0002 and 0.1673 respectively. It was 0.0071 for FMF-patients vs. FMF-amyloidosis. When 694 M/V homozygous nonamyloid-FMF group was compared with 694 M/V carriers of the FMF-amyloidosis group, the difference was 0.049. When carrying TT allele was considered, the difference between controls vs. FMF patients and FMF-amyloidosis patients were 0.0001 and 0.58. It was 0.0003 for FMF patients vs. FMF-amyloidosis. When 694 M/V homozygous nonamyloid-FMF group was compared with 694 M/V carriers of the FMF-amyloidosis group, the difference was 0.03. Carrying SAA -13T in homozygote state revealed a 7.9 (95% CI 3.6 -17.5) fold risk for the occurrence of amyloidosis when compared with FMF patients without amyloidosis. This was 8.75 (95% CI 3.0 - 25.1) when 694 M/V homozygotes were taken into consideration. Our data revealed that the genotype SAA1 -13T has at least an effect on the development of amyloidosis. As more data on this polymorphism accumulate, we will understand its effect on the pathogenesis of amyloidosis in FMF.

The major complication of familial Mediterranean fever (FMF) is AA amyloidosis. The influence of FMF gene (MEFV) mutations and/or unknown environmental factors and other genetic modifiers are likely to affect the phenotypic variations of the disease and the development of amyloidosis. Serum amyloid A is a serum precursor of AA amyloid that is induced by inflammatory cytokines including TNF-alpha. Our analysis of SAA1.1 frequency in Turkish FMF-amyloidosis patients, revealed a higher frequency compared to non FMF-amyloidosis patients but the difference was not significant. On the other hand, the distribution of SAA1.1 homozygosity among FMF-amyloidosis patients was 55.5% compared to FMF-non-amyloidosis patients (30.8%) which was statistically significant revealing a 2.5 fold risk for the occurrence of amyloidosis. There was no significant difference between the controls and FMF patients with and without amyloidosis for the TNF-alpha-308 G-A allele. It is worth noting that all TNF-alpha-308 G-A carriers (n = 6) in FMF-amyloidosis group have SAA1.1 homozygosity compared to 2/11 in FMF-non-amyloidosis group. Further evaluation of these polymorphisms may have importance and need further study.

Objective: Familial Mediterranean fever (FMF) is an autosomal recessive disorder of childhood characterized by attacks of fever and serositis. Renal amyloidosis is the most important complication of the disease that determines the prognosis., Methods: Forty-eight Turkish FMF patients with amyloidosis who have been followed at the two hospitals in Ankara were included in this study., Results: All patients with amyloidosis had been symptomatic for FMF at the time of the diagnosis (Phenotype I), none had received regular colchicine therapy and all presented with proteinuria. Ten of them had asymptomatic proteinuria; 38 had nephrotic syndrome and 8 of them had renal insufficiency (CRI) as well, at the time of the diagnosis. Regular colchicine therapy was commenced to all of the patients. At the end of observation period of 4.5 +/- 2.23 years (range 2-12 yrs) on treatment, nephrotic syndrome resolved in 13 patients and proteinuria was lost in 5 of them. None but 2 of the patients who were diagnosed at proteinuric stage progressed to end stage renal failure (ESRF). Seven MEFV mutations (M694V, M680I, V726A, M694I, K695R, R761H, E148Q) were systematically investigated in 32 patients. Six of the seven studied mutations were found in these patients and clinical diagnosis was confirmed by mutation analysis in 24 patients. Eight patients were found to have mutations on one of the alleles., Conclusion: Amyloidosis is the most serious complication of FMF. Colchicine treatment ameliorates the progression of renal disease in the patients who presented with proteinuria and even with nephrotic syndrome. No correlation between the outcome of the patients with nephrotic syndrome and the degree of proteinuria and/or serum albumin levels at the initiation of treatment were noted. Progression to ESRF seems inevitable despite colchicine therapy after the development of CRI in patients with FMF associated amyloidosis.

Progressive systemic amyloidosis is the most important complication of familial Mediterranean fever that inevitably leads to chronic renal failure. Initial studies have suggested that the presence of the Met694Val mutation carry a significant risk for the development of amyloidosis. On the contrary, our data revealed that there was no dominance of any MEFV mutation in relation to amyloidosis. The difference between our mutation data and others led us to study a polymorphism in Turkish population that might be a risk factor for the occurrence of amyloidosis. As some of the previously reported exonic polymorphisms in other disease states found to increase the genetic susceptibility, we aimed to study Ala138Gly of the MEFV gene. Our study group consisted of 124 FMF patients, of which 47 had amyloidosis. Eighty-one individuals without any familial history of FMF were included as control group. There was no statistically significant difference between healthy controls and FMF patients for the Ala138Gly polymorphism (p=0.9). However, when FMF/amyloidosis patients (n:47) were taken as another group, the difference was significant (p= 0.01) indicating that the carriers of 138Gly are more prone to amyloidosis [odds ratio 3.1 (CI 95% 1.57-5.75)]., (Copyright 2001 Wiley-Liss, Inc.)

We compared the frequencies of seven MEFV mutations (M694V, M680I, V726A, M694I, K695R, R761H, E148Q) and the clinical findings in 20 Turkish FMF patients who had not developed amyloidosis by the age of 40 years in the absence of colchicine therapy, with those in 27 Turkish amyloidosis patients. No mutation frequency, including that of M694V, was different between the two groups. Family history of amyloidosis and parental consanguinity were noted to be higher in the amyloidosis group. The seven mutations do not appear to be sufficient to explain the development of amyloidosis in Turkish FMF patients. Other genetic factors may be important for this association.