The significance of paired MEFV mutations in individuals without symptoms of familial Mediterranean fever

The Influence of Coexisting Familial Mediterranean Fever on Crohn's Disease: Data From an FMF Endemic Area

GOAL

The goal of this study was to evaluate the impact of coexisting familial Mediterranean fever (FMF) on Crohn's disease (CD) patients' phenotype and disease course in an endemic region for FMF.

BACKGROUND

CD and FMF are inflammatory diseases characterized by recurrent abdominal pain and fever attacks. The impact of coexisting FMF on CD patients' phenotype and disease course is currently unknown.

MATERIALS AND METHODS

We reviewed the medical records of 210 adult CD patients who were regularly followed up at a tertiary gastroenterology clinic between November 2006 and April 2018. The patients were divided into FMF positive (CD-FMF) and FMF negative (CD-control) groups. The severity of CD was assessed by the rate of hospitalization because of CD, the need for biological therapy, and whether surgery was performed for CD.

RESULTS

Eight (3.8%) of 210 CD patients have concomitant FMF, which is 35 to 40 times higher than expected in an endemic region for FMF. Baseline demographic parameters, location/behavior of the CD, and initial therapeutic regimens were similar between the 2 groups. The prevalence of peripheral arthritis was significantly higher in CD-FMF group (37.5% vs. 10.4%, respectively, P =0.04). A significantly greater proportion of the CD-FMF patients had received biological therapy (50% vs. 11.9%; P =0.012). Steroid dependence and CD-related hospitalization rates in the CD-FMF group were relatively higher but were not statistically significant (37.5% vs. 15.3 and 62.5% vs. 41.1%).

CONCLUSIONS

Our findings indicate that the disease course of CD tends to be more severe in patients with coexisting FMF.

Familial Mediterranean Gene (MEFV) Mutation in Parents of Children with Familial Mediterranean Fever: What Are the Exceptions?

Objectives

Familial Mediterranean Fever (FMF) is one of the most prevalent periodic fever syndromes; MEFV, the responsible gene for the disease, is in the short arm of chromosome16. In the considerable count of the FMF patients, only one mutation is found in the MEFV and parents, who were the obligatory carriers for that mutation, were asymptomatic. The aim of this study was to evaluate these asymptomatic parents in regard to mutation in MEFV gene and similarity between parents and offspring patients.

Methods

In this cross-sectional study, asymptomatic parents of FMF patients enrolled the study were referred to periodic fever clinic or pediatric rheumatology clinic of Tehran University of Medical Sciences. The patients should have at least one mutation in MEFV gene and none of them had any family history of autoinflammatory disease. Twelve mutations in MEFV gene were assessed in the parents by Vienna Lab FMF Strip Assay kit by MAS PCR/Reverse hybridization.

Results

Forty-three patients and their parents participated in the study. Sixty-three percent (27) of patients were male. Onset of disease symptoms in 31 patients (72%) was before 4 years of old. Nine (21%) of the patients had homozygote, 16 (37%) compound heterozygote, and 17(40%) heterozygote for MEFV mutation; there was a case of complex alleles mutations (2%). M694V/M694V in 4 patients (9%) was the most homozygote genotype, and M694V/R761H in 4 (9%) and E148Q in 7 (16%) were the most compound heterozygote and heterozygote genotype, respectively. M694V, M680I, and E148Q were the most mutation in the parents. Overall, 41 patients had mutations similar to their parents' mutation, except 2 whose parents had no mutation, but a patient did.

Conclusion

It seems that occurrence of new mutations in offspring is not prevalent among FMF patients and there are other reasons for different clinical presentation in similar mutation carriers. On the other hand, in ethnicities with high prevalence of FMF, new mutation in descendant may occur, infrequently.

Prevalence of common MEFV mutations and carrier frequencies in a large cohort of Iranian populations

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disorder caused by mutations in the MEFV gene. The disease is especially common among Armenian, Turkish, Jewish and Middle East Arab populations. To identify the frequency and the spectrum of common MEFV mutations in different Iranian populations, we investigated a cohort of 208 unselected asymptomatic individuals and 743 FMF patients. Nine hundred and fifty-one samples were analysed for the presence of 12 MEFV mutations by PCR and reverse-hybridization (FMF StripAssay, ViennaLab, Vienna, Austria). Confirmatory dideoxy sequencing of all MEFV gene exons was performed for 39 patients. Fifty-seven (27.4%) healthy individual carried mutant MEFV alleles. Three hundred and ninety-one (52.6%) FMF patients were found positive for either one (172/743; 23.1%), two or three MEFV mutations. Using dideoxy sequencing, three novel variants, A66P, R202W and H300Q, could be identified. Our analysis revealed an allele frequency and carrier rate of 15.6 and 27.4%, respectively, among healthy Iranians. Still moderate compared to neighbouring Armenia, but higher than in Turkey or Iraq, these data suggest that FMF is remarkably common among Iranian populations. E148Q was most frequent in the group of healthy individuals, whereas M694V was the most common mutation among FMF patients, thereby corroborating previous studies on MEFV mutational spectra in the Middle East. Accordingly, MEFV mutations are frequent in healthy Iranian individuals across different ethnic groups. Based on this finding, the awareness for FMF and the implementation of augmented carrier screening programmes considering the multiethnic nature of the Iranian population should be promoted.

Update on Pyrin Functions and Mechanisms of Familial Mediterranean Fever

Mutations in the MEFV gene, which encodes the protein named pyrin (also called marenostrin or TRIM20), are associated with the autoinflammatory disease familial Mediterranean fever (FMF). Recent genetic and immunologic studies uncovered novel functions of pyrin and raised several new questions in relation to FMF pathogenesis. The disease is clinically heterogeneous reflecting the complexity and multiplicity of pyrin functions. The main functions uncovered so far include its involvement in innate immune response such as the inflammasome assemblage and, as a part of the inflammasome, sensing intracellular danger signals, activation of mediators of inflammation, and resolution of inflammation by the autophagy of regulators of innate immunity. Based on these functions, the FMF-associated versions of pyrin confer a heightened sensitivity to a variety of intracellular danger signals and postpone the resolution of innate immune responses. It remains to be demonstrated, however, what kind of selective advantage the heterozygous carriage conferred in the past to be positively selected and maintained in populations from the Mediterranean basin.

The role of IL-4 gene 70 bp VNTR and ACE gene I/D variants in Familial Mediterranean fever

Familial Mediterranean fever (FMF) is characterized by recurrent attacks of fever and inflammation in the peritoneum, synovium, or pleura, accompanied by pain. It is an autosomal recessive disease caused by mutations in the MEFV (MEditerranean FeVer) gene. Patients with similar genotypes exhibit phenotypic diversity. As a result, the variations in different genes could be responsible for the clinical findings of this disease. In previous studies genes encoding Angiotensin-Converting Enzyme (ACE) and IL-4 (Interleukin-4) were found to be associated with rheumatologic and autoimmune diseases. In the present study we hypothesized whether ACE I/D or IL-4 70 bp variable tandem repeats (VNTR) genes are associated with FMF and its clinical findings in Turkish patients. Genomic DNA obtained from 670 persons (339 patients with FMF and 331 healthy controls) was used in the study. Genotypes for an ACE gene I/D polymorphism and IL-4 gene 70 bp VNTR were determined by polymerase chain reaction with specific primers. To our knowledge, this is the first study examining ACE gene I/D polymorphism and IL-4 gene 70 bp VNTR polymorphism in FMF patients. As a result, there was a statistically significant difference between the groups with respect to genotype distribution (p<0.001). According to our results, ACE gene DD genotype was associated with an increased risk in FMF [p<0.001; OR (95%): 7.715 (4.503-13.22)]. When we examined ACE genotype frequencies according to the clinical characteristics, we found a statistically significant association between DD+ID genotype and fever (p=0.04). In addition IL-4 gene P1P1 genotype was associated with FMF (p<0.001). We propose that D allele or DD genotype of ACE gene and P1 allele or P1P1 genotype of IL-4 gene may be important molecular markers for susceptibility of FMF.

Evaluation of common mutations in the Mediterranean fever gene in Multiple Sclerosis patients: is it a susceptibility gene?

PURPOSE

Multiple Sclerosis (MS) is a disease of the central nervous system characterized by multiple areas of inflammation and demyelination in the white matter of the brain and spinal cord. MEFV gene, which is the main factor in familial Mediterranean fever, is an intracellular regulator of inflammation. This study was designed to determine if known mutations in pyrin domain of MEFV gene are involved in MS and associated with MS morbidity.

METHODS

Fifty-three patients with MS and 66 healthy subjects, who were all Turkish, were included in this study. Five pyrin gene mutations (E148Q, M680I, M694V, M694I and V726A) were detected in the patients and controls by using the PRONTO FMF Basic Kit according to the manufacturer's instructions.

RESULTS

Pyrin gene mutations were found in 20 of the 53 MS patients (38%) and in seven of the 66 healthy subjects (11%). The frequency of total pyrin domain mutations was significantly higher in the MS patients than in the healthy subjects (p<0.0001). The frequencies of M694V, E148Q and V726A mutations were significantly higher in the patients than in the healthy subjects (p=0.02, p=0.013, p=0.004 respectively). The mean time to reach EDSS score 3.0 was earlier in the patients with MEFV gene mutation (p=0.02) and the relapse rate was slightly higher among the MS patients carrying MEFV gene mutation (p=0.04).

CONCLUSION

The results of this study supported the hypothesis that MS patients with MEFV mutation seem to have the susceptibility to develop a more progressive disease. Moreover, these data suggest that MEFV mutations may increase the risk of MS development.

[Molecular diagnostics of hereditary fever syndromes. Familial Mediterranean fever (FMF), hyperimmunoglobulin D syndrome (HIDS), tumor necrosis factor receptor-associated periodic syndrome (TRAPS), cryopyrin-associated periodic syndrome (CAPS: FCAS, MWS, NOMID/CINCA)]

Periodic episodes of fever and inflammation can have a genetic origin. Nowadays, the identification of the causative genetic variants in the majority of cases allows molecular genetic confirmation of the clinical diagnosis, which enables approaches with specific drug treatment and improves patient compliance as well as genetic counseling. Besides a detailed clinical examination a medical history including family history and an assessment of the ethnic origin are required. In order to make genetic testing straightforward and cost effective an iterative procedure should be followed which should include, in addition to clinical data, the frequencies of causative mutations in the various gene segments involved.

Pyrin and ASC co-localize to cellular sites that are rich in polymerizing actin

Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by mutations in the MEFV locus, which encodes the protein pyrin. While it is known that pyrin is expressed in myeloid cells and several fibroblastic cell types, the exact function of pyrin in these cells and the mechanism underlying the pathological effect of pyrin mutations have yet to be revealed. Here, we document that in migrating human monocytes, pyrin protein is dramatically polarized at the leading edge, where it co-localizes with polymerizing actin. ASC (Apoptosis-associated Speck protein with CARD domain), a known pyrin-interacting protein and a critical component of the inflamma-some, is also located at the leading edge in migrating monocytes. Similarly, both pyrin and ASC concentrate in dynamically polymerizing actin-rich tails generated by Listeria monocytogenes. Pyrin's B-box and coiled-coil region is required for its association with Listeria tails. Pyrin also binds, with low affinity and via the same domains, to actin, VASP, and Arp3. Though disease-causing mutations in pyrin do not appear to alter its localization to the leading edge or to Listeria rocket tails, they could potentially have important functional consequences in the context of processes such as migration and cell synapse formation. The co-localization of pyrin and ASC together at such sites may provide an important link between cytoskeletal signaling and inflammasome function.

Clinical and subclinical inflammation in patients with familial Mediterranean fever and in heterozygous carriers of MEFV mutations

OBJECTIVE

To prospectively monitor inflammatory activity over a prolonged period in a cohort of Turkish patients with FMF, their healthy relatives and healthy controls and to relate this to their MEFV genotypes.

METHODS

43 patients with FMF and 75 of their asymptomatic relatives underwent fortnightly assessments and venesection for measurement of CRP and SAA over 5 months. 50 unrelated healthy population matched controls were also studied. MEFV genotyping was performed on all participants and comparisons were made between the different groups.

RESULTS

Paired MEFV mutations were detected in 84% of FMF patients and single mutations in 12%. Substantial acute phase reactivity was seen among the patients with FMF during attacks (median SAA 693 mg/l, CRP 115 mg/l). Between attacks there was also some inflammatory activity (median SAA 6 mg/l, CRP 4 mg/l). Among healthy controls 16% were heterozygotes for MEFV mutations and 4% had two mutations. As expected there was a substantial carrier rate among healthy relatives with mutations detected in almost 92%. Asymptomatic MEFV heterozygotes had elevated acute phase proteins compared to wild type subjects.

CONCLUSION

Substantial sub-clinical inflammation occurs widely and over prolonged periods in patients with FMF, indicating that the relatively infrequent clinically overt attacks represent the 'tip of the iceberg' in this disorder. Both basal and peak acute phase protein concentrations were greater in MEFV heterozygotes than in wild-type controls, regardless of mutation demonstrating a 'pro-inflammatory' phenotype among FMF carriers. Upregulation of the acute phase response among carriers of FMF may augment their innate host response and contribute to better resistance to infection.

Allelic variants in genes associated with hereditary periodic fever syndromes as susceptibility factors for reactive systemic AA amyloidosis

We investigated the hypothesis that low-penetrance mutations in genes (TNFRSF1A, MEFV and NALP3/CIAS1) associated with hereditary periodic fever syndromes (HPFs) might be risk factors for AA amyloidosis among patients with chronic inflammatory disorders, including rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), Crohn's disease, undiagnosed recurrent fevers and HPFs themselves. Four of 67 patients with RA plus amyloidosis had MEFV variants compared with none of 34 RA patients without amyloid (P value=0.03). The E148Q variant of MEFV was present in two of the three patients with TNF receptor-associated periodic syndrome (TRAPS) complicated by amyloid in two separate multiplex TRAPS families containing 5 and 16 affected members respectively, and the single patient with Muckle-Wells syndrome who had amyloidosis was homozygous for this variant. The R92Q variant of TNFRSF1A was present in two of 61 JIA patients with amyloidosis, and none of 31 nonamyloidotic JIA patients. No HPF gene mutations were found in 130 healthy control subjects. Although allelic variants in HPFs genes are not major susceptibility factors for AA amyloidosis in chronic inflammatory disease, low-penetrance variants of MEFV and TNFRSF1A may have clinically significant proinflammatory effects.

Familial Mediterranean fever (FMF) in Turkey: results of a nationwide multicenter study

Familial Mediterranean fever (FMF) is an autosomal recessive disease that is prevalent among eastern Mediterranean populations, mainly non-Ashkenazi Jews, Armenians, Turks, and Arabs. Since a large proportion of all the FMF patients in the world live in Turkey, the Turkish FMF Study Group (FMF-TR) was founded to develop a patient registry database and analyze demographic, clinical, and genetic features. The cohort was composed of 2838 patients (mean age, 23.0 +/- 13.33 yr; range, 2-87 yr), with a male:female ratio of 1.2:1. There was a mean period of 6.9 +/- 7.65 years from disease onset to diagnosis; the period was about 2 years shorter for each decade since 1981. Ninety-four percent of patients were living in the central-western parts of the country; however, their familial origins (70% from the central-eastern and Black Sea regions) reflected not only the ongoing east to west migration, but also the historical roots of FMF in Turkey. Patients' clinical features included peritonitis (93.7%), fever (92.5%), arthritis (47.4%), pleuritis (31.2%), myalgia (39.6%), and erysipelas-like erythema (20.9%). Arthritis, arthralgia, myalgia, and erysipelas-like erythema were significantly more frequent (p < 0.001) among patients with disease onset before the age of 18 years. Genetic analysis of 1090 patients revealed that M694V was the most frequent mutation (51.4%), followed by M680I (14.4%) and V726A (8.6%). Patients with the M694V/M694V genotype were found to have an earlier age of onset and higher frequencies of arthritis and arthralgia compared with the other groups (both p < 0.001). In contrast to other reported studies, there was no correlation between amyloidosis and M694V homozygosity in this cohort. However, amyloidosis was still remarkably frequent in our patients (12.9%), and it was prevalent (27.8%) even among the 18 patients with a disease onset after age 40 years. Twenty-two patients (0.8%) had nonamyloid glomerular diseases. The high prevalence of vasculitides (0.9% for polyarteritis nodosa and 2.7% for Henoch-Schonlein purpura) and high frequency of pericarditis (1.4%) were striking findings in the cohort. Phenotype II cases (those patients with amyloidosis as the presenting or only manifestation of disease) were rare (0.3% or less). There was a high rate of a past diagnosis of acute rheumatic fever, which suggested a possible misdiagnosis in children with FMF presenting with recurrent arthritis. To our knowledge, this is the largest series of patients with FMF reported from 1 country. We describe the features of the disease in the Turkish population and show that amyloidosis is still a substantial problem.

Musculoskeletal disorders in secondary amyloidosis and hereditary fevers

Amyloidosis remains a severe potential complication of many chronic inflammatory disorders, foremost of rheumatoid arthritis. It is not exactly known why some patients develop a progressive amyloidosis while others do not, although latent deposits may be present. It is likely that more potent anti-inflammatory drugs recently used in rheumatoid arthritis have led to a decrease of amyloid-associated (AA) amyloidosis. However, overt amyloidosis remains a severe complication of some chronic inflammatory disorders and it has a poor prognosis. Hereditary fevers are a group of diseases characterized by intermittent bouts of clinical inflammation with focal organ involvement, mainly abdomen, musculoskeletal system and skin. The most frequent is familial Mediterranean fever which affects patients of Mediterranean descent all over the world. Three other types have been recently characterized clinically as well as genetically. A thorough diagnosis is warranted, as clinical and therapeutic management is specific for each of these diseases.