Familial Mediterranean fever gene mutations in north-eastern part of Anatolia with special respect to rare mutations

[Results of the systematic literature search as basis for the "Evidence-based treatment recommendations for familial Mediterranean fever patients with insufficient response or intolerability to colchicine" of the Society for Pediatric and Adolescent Rheumatology and the German Society for Rheumatology]

BACKGROUND

Familial Mediterranean fever (FMF) is a genetic disease of childhood and adulthood which is relatively rare in Germany. It is characterized by recurrent febrile attacks, peritonitis, pleuritis and arthritis. The established treatment with colchicine is effective and well-tolerated by most patients; however, some patients do not adequately respond or do not tolerate this treatment. Biologics can be considered for some of these patients. The Society for Pediatric and Adolescent Rheumatology (GKJR) and the German Society for Rheumatology (DGRh) have agreed to develop joint recommendations for this specific clinical situation.

AIM

Implementation of a systematic literature search (SLR) on the basis of the EULAR recommendations published in 2016 as the foundation for the development of evidence-based treatment recommendations for FMF patients with insufficient response or intolerance to colchicine.

METHODS

The SLR was performed using references from various databases as an update of the SLR carried out by EULAR up to 2014, whereby all articles must have been published between 1 January 2015 and 31 December 2017. The Rayyan abstract tool for the preselection and the classification of the Oxford Centre for Evidence Based Medicine 2009 were used for the preparation of the evidence tables.

RESULTS

The search yielded 360 hits and after duplicate matching 263. A total of 88 publications were included (34%) and 102 excluded (39%), a review of the full publication was necessary for a further 73 (28%) and 43 were discussed more intensively. Finally, 64 publications (24%) remained. A total of 4 case-control studies, 31 cohort studies, 8 case series, 7 controlled studies (including 5 abstracts), 10 reviews, 4 meta-analyses and systematic reviews were accepted.

DISCUSSION

The SLR was carried out in a scientifically accurate and transparent manner according to international standards. The SLR proved to be a good basis for a consensus on the 5 overarching principles and the 10 recommendations, so that the joint activity of the GKJR and DGRh was successfully and even promptly concluded. The recommendations are a solid basis for treating patients of all ages with FMF. The explanations on the problem of colchicine resistance play an important role here.

The Spectrum of MEFV Gene Mutations and Genotypes in the Middle Northern Region of Turkey

Objective

Familial Mediterranean fever (FMF) is a common, inherited, autosomal recessive inflammatory disease in children. The diagnosis of FMF is based on clinical features and positive family history supported with genetic testing. This study aimed to determine the frequency and distribution of Mediterranean fever (MEFV) gene alterations of a city in Northern Anatolia.

Materials and Methods

We evaluated MEFV gene mutations in 374 children preliminary diagnosed as FMF by a commercial kit based on real-time polymerase chain reaction technique in a one-year period, and screened 12 mutations.

Results

At least one mutation was detected in 213 patients (57%) and 38 genotypes with 11 distinct mutations.A total of 137 (64. 3%) of mutation-positive children were heterozygous, 45 (21. 1%) were compound heterozygous, and 2 (0.9%) were complex heterozygous; and 14 (6.4%) patients were homozygous, 6 (2.8%) were compound homozygous, and 3 (1.4%) were complex homozygous. With a frequency of 50.1%, R202Q was the most common mutation. Also, R202Q/M694V was the most common compound heterozygous genotype. In 43 alleles, R202Q-M694V mutations were found to be in linkage disequilibrium. In our cohort, M694V, E148Q, V726A, and M680I (G/C) were other common mutations; whereas F479L, A744S, K695R, P369S, M694I, and R761H were the rare mutations. None of our patients had M680I (G/A) mutation.

Conclusion

We determined the most common MEFV alteration prevalence in children of our region for the first time. The high R202Q mutation and linkage disequilibrium (LD) rates were the remarkable results of this study.

The distribution of MEFV mutations in Turkish FMF patients: multicenter study representing results of Anatolia

Background/aim

The distribution of Mediterranean fever (MEFV) gene mutations in Turkish familial Mediterranean fever (FMF) patients varies according to geographic area of Turkey. There is a need for highly representative data for Turkish FMF patients. The aim of our study was to investigate the distribution of the common MEFV mutations in Turkish FMF patients in a nationwide, multicenter study.

Materials and methods

Data of the 2246 FMF patients, from 15 adult rheumatology clinics located in different parts of the country, were evaluated retrospectively. The following mutations have been tested in all patients: M694V, M680I, M694I, V726A, and E148Q.

Results

There were 1719 FMF patients with available genetic testing. According to the genotyping, homozygous M694V, present in 413 patients (24%), was the most common mutation . One hundred and fifty-four (9%) of patients had no detectable mutations. Allele frequencies of common mutations were: M694V (n = 1529, 44.5%), M680I (n = 423, 12.3%), V726A (n = 315, 9.2%), E148Q (n = 214, 1%), and M694I (n = 12, <1%).

Conclusion

In this large-scale multicenter study, we provided information about the frequencies of common MEFV gene mutations obtained from adult Turkish FMF patients. Nearly half of the patients were carrying at least one M694V mutations in their alleles.

A case of adult onset Still's disease with mutations of the MEFV gene who is partially responsive to colchicine

RATIONALE

Familial Mediterranean fever (FMF) and adult onset Still's disease (AOSD) have overlapping features, and are categorized as being on the spectrum of autoinflammatory diseases (AIDs). FMF is more prevalent in the Mediterranean region but rarely, described in the Chinese population.

PATIENT CONCERNS

We present an interesting case of a Han Chinese AOSD patient with episodic fever, wheals, and polyarthritis for 2 years.

DIAGNOSIS

Sequencing analysis found exon 2 mutations of the MEFV gene (c.329T>C [L110P], and c.442G>C [E148Q]).

INTERVENTION

Her arthritis was well-controlled with colchicine treatment, but fever, and rashes were not.

OUTCOMES

She eventually received tocilizumab, in addition to colchicine, and her symptoms completely disappeared.

LESSONS

MEFV mutations may exist in AOSD patients, and treatment with colchicine might be helpful in such patients.

Increased Frequency of MEFV Genes in Patients with Epigastric Pain Syndrome

Atypical clinical forms of familial Mediterranean fever (FMF) can be misdiagnosed as therapy-resistant epigastric pain syndrome (EPS) for they share many of the same clinical features, such as abdominal pain. Thus, we aimed to determined the frequency of FMF in patients who were followed with a diagnosis of therapy-resistant EPS. Seventy-five patients with therapy-resistant EPS and 20 controls were involved in the study. To detect the FMF in patients with therapy-resistant EPS, Tel-Hashomer criteria, family history of FMF were researched and recorded. We performed performed MEFV gene analysis on all patients. Forty-three patients with EPS (57.3%) had MEFV gene mutations and the carrier rate was 30.0%. The most common MEFV gene alteration was R202Q (55.8%), followed by E148Q (16.2%), R761H (16.2%), V726A (9.3%), M680I (9.3%) and M694V (4.6%). Rarely seen mutations in the Turkish population were also identified: K695R (2.3%), L110P (2.3%) and G304R (2.3%). Eight patients with EPS were diagnosed with FMF and started on colchicine therapy. Three patients with compound heterozygosities for three mutations, two patients with compound heterozygosities for two mutations (K695R/ V726A and R202Q/ R761H), one patient with homozygous R202Q, one patient with heterozygous R202Q mutation and one patient with non- R202Q heterozygous mutation (G304R/-) had clinical FMF symptoms and were started on colchicine therapy. Patients who have therapy-resistant EPS should also be questioned about FMF, especially in high risk populations.

MEFV mutations and their relation to major clinical symptoms of Familial Mediterranean Fever

Familial Mediterranean fever is a common hereditary disease in Turkey. To date, different mutational spectrum of MEFV gene was observed in studies carried out in different regions of Turkey but in most of these studies association of clinical symptoms of FMF to mutant genotypes have not been investigated in details. Here we report the MEFV gene variations in exons 2, 3, 5 and 10 and their relations to major clinical symptoms of FMF in 514 unrelated (245 males and 269 females) Turkish patients. MEFV mutations were found in 45% (n=230) of patients and 55% (n=284) of patients did not have any mutations. One hundred and thirty-seven (60%) patients were heterozygous, 57 (24.7%) patients were compound heterozygous, 33 (14%) patients were homozygous and 3 (1.3%) patients were having a complex genotype. Allele frequencies of MEFV mutations were M694V (48%), E148Q (18%), M680I (15%), V726A (12.5%), P369S (3.3%), R761H (0.9), K695R (0.9), E148V (0.9) and A744S (0.5%). Abdominal pain (76%) and fever (58%) were two most seen complications among patients followed by arthritis (28%) and chest pain (19%). Almost all major clinical symptoms of FMF were higher in patients with one or more M694V or M680I mutant allele. In contrast, patients having E148Q or V726A mutant allele showed fewer clinical FMF symptoms. Patients with P369S have higher abdominal pain, chest pain and fever than expected. Arthritis was high in K695R heterozygous genotype. One hundred and eighteen patients were carrying more than one polymorphic allele. The most common polymorphism was R202Q (13%). In addition, a novel heterozygous polymorphism at 564th nucleotide (C>T) of exon2 were found in 2 patients.