Amyloid A amyloidosis in a Japanese patient with familial Mediterranean fever associated with homozygosity for the pyrin variant M694I/M694I

Abstract

Familial Mediterranean fever (FMF) is an autoinflammatory disease common in eastern Mediterranean populations. The most severe complication is the development of secondary amyloid A (AA) amyloidosis. A 51-year-old Japanese male who had been suffering from periodic fever since in his twenties was referred to our hospital for proteinuria. Histological findings from renal biopsy revealed the deposition of AA amyloid fibrils, suggesting that renal dysfunction was due to AA amyloidosis. Gene analysis of the patient and his mother showed that both were homozygous for the M694I mutation in the MEFV gene. His mother was also a carrier of the SAA1.3 allele, which is not only a univariate predictor of survival but also a risk factor for the association of AA amyloidosis with rheumatoid arthritis in Japanese patients, and the SAA1-13T allele in the 13T/C polymorphism on the 5′-flanking region of the SAA1 gene. The patient was also a carrier of the SAA-13T allele. Colchicine resulted in not only an amelioration of the acute febrile attacks of FMF inflammation, but also an improvement in kidney dysfunction due to AA amyloidosis.