This is the first amino acid sequence analysis of an amyloid fibril protein from a Turkish patient with AA amyloidosis secondary to familial Mediterranean fever. Amyloid fibrils were isolated from spleen tissue and purified by gel filtration. The major protein constituent was found to be an 8 kD amyloid protein AA. Amino acid sequence analysis indicated that the Turkish AA protein is the product of apoSAA(1 alpha) gene with Val at position 52, Ala at position 57, Asp at position 60, and Phe Phe at positions 68 and 69. Two other analyses of AA amyloid from individuals with familial Mediterranean fever have been reported. One is consistent with products of both apoSAA(1 alpha) and apoSAA(1 gamma) genes, while the other is consistent with a product of apoSAA(2 beta) gene.