SAA1 alpha/alpha alleles in amyloidosis.

BACKGROUND: Amyloidosis, mainly AA type, is one of the common diseases in nephrology clinics in Turkey. AA type amyloidosis is a complication of various chronic infections or inflammatory diseases such as familial Mediterranean fever (FMF), rheumatoid arthritis (RA), tuberculosis and bronchiectasis. A controversy exists in the literature regarding the relationship between SAA1 genotypes and AA type amyloidosis. This study aimed to investigate SAA1 gene polymorphism in different patient groups: 1) amyloidosis, 2) FMF and 3) healthy controls. METHODS: Eighty-two patients from the three groups were included in the study: 1) amyloidosis, 2) FMF without amyloidosis, and 3) healthy controls. SAA1 genotypes were studied by the polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: The homozygous alpha/alpha genotype is the most common SAA1 genotype among patient groups with amyloidosis, and the alpha/alpha genotype frequency is significantly higher than in healthy controls (68 vs. 38%, p<0.05). CONCLUSIONS: The SAA1 alpha/alpha genotype is a risk factor for AA type amyloidosis in Caucasoid populations and more studies are needed to investigate why the gamma/gamma genotype is associated with AA type amyloidosis in Japan.