Clinical study of 7 cases of familial Mediterranean fever with MEFV gene mutation

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

Introduction

Familial 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.

Methods

We analyzed the MEFV genotypes and clinical manifestations in 116 patients clinically diagnosed as having FMF and with at least one mutation.

Results

The most frequent mutation in Japanese patients was E148Q (40.2%), followed by M694I (21.0%), L110P (18.8%), P369S (5.4%), and R408Q (5.4%). In contrast, common mutations seen in Mediterranean patients, such as M694V, V726A, and M680I, were not detected in this population. The clinical features with M694I were associated with more severe clinical course compared to those seen with E148Q. P369S/R408Q showed variable phenotypes with regard to both clinical manifestations and severity. Patients with M694I showed a very favorable response to colchicine therapy, while those with P369S and R408Q did not.

Conclusions

Clinical 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.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0439-7) contains supplementary material, which is available to authorized users.

Familial mediterranean fever: a fascinating model of inherited autoinflammatory disorder

BACKGROUND

Familial Mediterranean fever (FMF) is a rare inherited autosomal recessive autoinflammatory disorder characterized by recurrent and self-limited episodes of fever and painful serositis, lasting 1-3 days. FMF occurs almost exclusively among ethnic groups of the Mediterranean basin, although cases have also been found in Japan and Korean populations. Diagnosis is based on clinical features, response to colchicine and genetic analysis. Novel drugs are emerging, allowing better management of colchicine-resistant/colchicine-intolerant patients. This review aims to attract the attention of the readers on differential diagnosis and management of patients with FMF.

METHODS

The current state-of-the-art on FMF is outlined, with respect to epidemiological, genetic, pathophysiological and therapeutic characteristics, based on critical analysis of solid scientific literature.

RESULTS

FMF is more frequent than it was thought before. The phenotypic expression of M694V is more severe than that of V726A. Patients with M694V/M694V homozygosity are exposed to a higher risk of developing renal amyloidosis, arthritis, dermatologic and oral lesions, higher fever and more frequent painful attacks. Life-long therapy with colchicine (1·0-2·4 mg/day) is effective and safe to prevent recurrent attacks and renal amyloidosis and to reverse proteinuria. In nonresponder patients, alternative novel approaches include interleukin-1 receptor antagonist anakinra and the interleukin-1 decoy receptor rilonacept.

CONCLUSIONS

The prognosis of FMF is normal if AA amyloidosis is prevented. Colchicine remains the first-line therapy to treat pain and prevent amyloidosis. A follow-up should include clinical evaluation, therapeutic adjustments, measurement of serum amyloid A and proteinuria.

An atypical familial Mediterranean fever patient who developed ulcers in the terminal ileum and recurrent abscess-like lesions in multiple organs

We herein describe the case of a 25-year-old woman who suffered from atypical familial Mediterranean fever for more than a decade. She presented with a periodic fever, abdominal pain and persistent ulcers in the terminal ileum. Colchicine was effective, and familial Mediterranean fever was diagnosed. A genetic study showed a heterozygous E148Q mutation in the MEFV gene. Multiple, recurrent, abscess-like lesions developed asynchronously in the spleen, liver, and a lung. Infliximab was administered when colchicine treatment became ineffective. However, infliximab treatment soon became ineffective, probably because antibodies were generated against it. Therefore, etanercept treatment was started, and the patient showed an immediate response.

Familial Mediterranean fever with onset at 66 years of age

The patient was a 68-year-old woman who had experienced recurrent febrile episodes since 66 years of age. Despite various examinations and treatments, the etiology remained unclear. Further examinations following another referral failed to uncover the cause. Therefore, despite her age, it was presumed that she had familial Mediterranean fever. An analysis of the familial Mediterranean fever (MEFV) gene detected heterozygous L110P, E148Q, and R202Q mutations. No further febrile episodes occurred after colchicine treatment was initiated. Familial Mediterranean fever presenting in patients in their sixties is extremely rare.

Clinical and Genetic Features of Familial Mediterranean Fever in Japan

Objective.

Familial Mediterranean fever (FMF) is thought to be a rare disorder in Japan, and the clinical features of Japanese patients with FMF remain unclear. Our aim was to elucidate the clinical characteristics of FMF in Japanese patients.

Methods.

We analyzed clinical and genetic data of 80 patients based on the results of a nationwide questionnaire survey and review of the literature.

Results.

From clinical findings of 80 Japanese patients, high-grade fever was observed in 98.8%, chest attacks (pleuritis symptoms) in 61.2%, abdominal attacks (peritonitis symptoms) in 55.0%, and arthritis in 27.5%. Twenty-four percent of patients experienced their first attacks before 10 years of age, 40% in their teens, and 36% after age 20 years. Colchicine was effective in many patients at a relatively low dose (< 1.0 mg/day). AA amyloidosis was seen in only 1 patient. Common MEFV mutation patterns were E148Q/M694I (25.0%), M694I alone (17.5%), and L110P/E148Q/M694I (17.5%), and no patient carried the M694V mutation, the most common mutation in Mediterranean patients with FMF.

Conclusion.

A larger than expected number of patients with FMF exist in Japan, and the clinical presentation of Japanese FMF patients seems to be relatively milder than those of Mediterranean FMF patients. AA amyloidosis rarely occurs in Japanese patients, probably due to difference in patterns of the MEFV genotype between Japanese and Mediterranean patients.

Familial Mediterranean fever in three Japanese patients, and a comparison of the frequency of MEFV gene mutations in Japanese and Mediterranean populations

We report on three Japanese patients (two families) with familial Mediterranean fever (FMF), a rare disease in the Far East. Two of the patients (siblings with definite FMF) were heterozygous for both E148Q and M694I, and the remaining patient (with probable FMF and no family history of the disease) was heterozygous for both P369S and R408Q. Although the M694I mutation is less common among Mediterranean populations, it was present in 22 (76%) of 29 Japanese patients with FMF (previously reported cases). We therefore investigated the allele frequency of M694I in the healthy Japanese population, as well as other FMF-causing mutations in exon 10 (M680I, M694V, and V726A) and polymorphisms (E148Q, P369S, and R408Q) of the Mediterranean fever gene (MEFV). The allele frequencies of disease-causing mutations, even M694I, were <0.001. While those of E148Q, P369S, and R408Q were 0.23, 0.057, and 0.054, respectively. Because of the low allele frequencies of disease-causing mutations, FMF is an extremely rare disease among Japanese individuals. However, FMF is an important component of hereditary autoinflammatory syndrome, and a diagnosis of FMF is crucial for the choice of treatment, because of the benefit of colchicine therapy.