Genotype-phenotype correlation in Japanese patients with familial Mediterranean fever: differences in genotype and clinical features between Japanese and Mediterranean populations.

[familial mediterranean fever]

IntroductionFamilial Mediterranean fever (FMF ) is a hereditary autoinflammatory disease characterized by recurrent self-limiting fever and serositis that mainly affects Mediterranean populations . Many patients with FMF have been reported in Japan due to increasing recognition of this condition and the availability of genetic analysis for the gene responsible , MEFV . The present study was performed to elucidate the clinical characteristics of Japanese FMF patients and to examine the precise genotype-phenotype correlation in a large cohort of Japanese FMF patients .MethodsWe analyzed the MEFV genotypes and clinical manifestations in 116 patients clinically diagnosed as having FMF and with at least one mutation .ResultsThe most frequent mutation in Japanese patients was E 148 Q (40 .2 %), followed by M 694 I (21 .0 %), L 110 P (18 .8 %), P 369 S (5 .4 %), and R 408 Q (5 .4 %). In contrast , common mutations seen in Mediterranean patients , such as M 694 V , V 726 A , and M 680 I , were not detected in this population . The clinical features with M 694 I were associated with more severe clinical course compared to those seen with E 148 Q . P 369 S /R 408 Q showed variable phenotypes with regard to both clinical manifestations and severity . Patients with M 694 I showed a very favorable response to colchicine therapy , while those with P 369 S and R 408 Q did not .ConclusionsClinical features and efficacy of treatment in Japanese FMF patients vary widely according to the specific MEFV gene mutation , and therefore genetic analysis should be performed for diagnosis in cases of Japanese FMF .