Molecular Patterns of MEFV Gene Mutations in Egyptian Patients with Familial Mediterranean Fever: A Retrospective Cohort Study

E148Q variant: a familial Mediterranean fever-causing mutation or a sequence variant?

Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disease, linked to mutations in the MEFV gene. The p.E148Q variant, found on exon 2, has an uncertain role in FMF, with debates on whether it is a benign polymorphism or a pathogenic mutation. This study aimed to assess the clinical characteristics and severity of FMF in patients homozygous for the p.E148Q variant and to evaluate the impact of the p.V726A variant in these patients. This retrospective cohort study analyzed data from electronic medical records at Carmel Medical Center, Israel. Patients who underwent genetic testing for FMF from November 2004 to December 2019 and had p.E148Q/p.E148Q or p.E148Q/p.E148Q + p.V726A variants were included. Disease severity was assessed using the Tel Hashomer Key to Severity Score. Statistical analyses compared clinical characteristics and severity between genotype groups. The study included 61 FMF patients, with 24 (39%) having p.E148Q/p.E148Q and 37 (61%) having p.E148Q/p.E148Q + p.V726A variants. The majority (72%) were Druze. Most patients (65.5%) exhibited mild disease, while 31.1% had moderate disease, with no cases of severe disease. Colchicine treatment significantly reduced CRP levels in all patients.

CONCLUSION

These findings suggest that the p.E148Q variant, whether alone or with p.V726A, generally results in mild to moderate FMF severity, supporting its pathogenic role in particular ethnicity. These results contribute to understanding the clinical significance of the p.E148Q variant and considering the patient's need for Colchicine treatment.

WHAT IS KNOWN

• The role of the p.E148Q variant in FMF is debated, with questions about whether it is a benign polymorphism or a pathogenic mutation. • The prevalence of MEFV variants can vary significantly among different ethnic groups.

WHAT IS NEW

• The p.E148Q variant has clinical significance in particular ethnicities, as supported by a significant reduction in CRP levels following colchicine treatment. • The p.E148Q variant, whether alone or with p.V726A, generally results in mild to moderate FMF severity.

Molecular analyses of MEFV gene mutation variants in Turkish population

BACKGROUND

Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disease primarily affecting individuals of Turkish, Armenian, Arab, and non-Ashkenazi Jewish descent, caused by mutations in the MEFV gene. The aim of this study was to review the common genotype distributions of MEFV variants and mutations in the Turkish population and evaluate rare mutations.

METHODS AND RESULTS

The study included 2984 patients who applied to Ankara University Ibni Sina Hospital Immunology Laboratory with clinical suspicion of FMF between 2004 and 2014. The data of patients from different regions of the country who were followed up in the immunology-rheumatology clinic with clinical suspicion and presumptive diagnosis of FMF were evaluated retrospectively. Patients were tested for all mutations in Exon 2 and Exon 10, including M694V, M680I, M694I, V726A, E148Q and R202Q. There were 2504 patients with FMF variant. According to genotyping, R202Q (n = 1567, 39.2%) was the most common mutation. The most common co-variant was the R202Q/M694V genotype (n = 507, 16.98%). Allele frequencies for MEFV mutations were as follows: R202Q (n = 1567, 39.2%), M694V (n = 1004, 25.1%), E148Q (n = 463, 11.5%), M680I (n = 354, 8.8%), V726A (n = 319, 7.9%), A744S (n = 51, 1.2%), R761H (N = 41, 1.0%), P706P (N = 25, 0.6%), E167D (N = 23, 0.5%), M694I (N = 23, 0.5%), and K695R (N = 20, 0.5%).

CONCLUSION

This research revealed the prevalence of both common and rare MEFV gene mutations in Turkish FMF patients in various age groups. R202Q was the most prevalent mutation.

R202Q prevalence in clinically diagnosed Familial Mediterranean Fever patients: 9 years of data analysis from 1570 patients living Central Black Sea region, Turkey

INTRODUCTION

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent self-limiting fever, peritonitis, arthritis, and erysipelas-like-erythema, common among ethnic groups such as Turkish, Armenian, Arab, and Jewish. The disease is caused by mutations in the MEFV gene encoding the Pyrin. This study examines the genotypes of FMF patients from Amasya, Turkey.

METHOD

According to the Tel Hashomer criteria, one thousand five hundred seventy patients (871 female, 699 male, mean age 21.2 ± 15.5 years) living in Amasya Province and the surroundings were screened for sequence variants in the entire MEFV gene. Besides, mutation types and alleles were evaluated with clinical findings.

RESULTS

MEFV mutations and polymorphisms were found in 1413 of the 1570 patients (90%). Among these patients, 5 (0.3%) were double homozygous, 152 (9.7%) were homozygous, 373 (23.8%) were double heterozygous, and 882 (56.2%) were heterozygous. The most frequent genotype was R202Q (960, 43.5%) followed by M694V (n = 412, 18.7%), E148Q (n = 321, 14.6%), and M680I (n = 200, 9.1%). The most common clinical symptoms were abdominal pain (96.4%) and fever (91.3%).

CONCLUSIONS

The fact that the R202Q genotype, which is compatible with the known FMF clinic, is frequently seen shows that it should be included in routine molecular screenings of the patients. Functional studies of the R202Q variant pyrin protein should be performed to understand FMF better. Finally, it is unclear whether the R202Q genotype might be regarded as a mutation while being approved as a polymorphism in the inFevers database.

Genotype Mutations in Palestinian Children with Familial Mediterranean Fever: Clinical Profile, and Response to Colchicine Treatment: A Retrospective Cohort Study

Background

Familial Mediterranean fever is a hereditary autoinflammatory disease affecting mainly Arabs, Turks, Armenians, and Jews with genotype-phenotype heterogeneity, presenting as recurrent episodes of fever along with polyserositis and rash. To date, more than 370 mutations in the MEFV gene have been recognized to cause the disease.

Methods

We conducted a retrospective cohort study involving 124 patients in Hebron, Palestine, diagnosed with FMF at the Al-Ahli, and Palestinian Red Crescent Society (PRCS) Hospitals.

Results

The median age of diagnosis was five years, presenting as abdominal pain (76.6%), fever (67.7%), joint pain and arthritis. Regarding MEFV gene mutations, we had 62 patients (50%) with heterozygous genotypes, 40 patients (32.3%) with homozygous phenotypes, 21 patients (16.9%) with compound heterozygous genotypes, and one was a missing state. Regarding variant frequencies, M694V was the most common one (43.4%), followed by E148Q (15.6%), V726A (5.7%), A744S (4.1%), and R202Q (4.1%). Positive family history was detected in 59 patients (54.6%), and there was no significant difference in zygosity regarding characteristics, consanguinity, and family history.

Conclusions

We affirm in this study of 124 children with FMF, abdominal pain, followed by fever, joint pain and arthritis were the main manifestations. Further, M694V, E148Q, V726A, A744S, and R202Q were the most frequent mutations, and carrying the M649V mutations is associated with a predisposition to other comorbidities. We believe that this study gives a pervasive overview of FMF in Palestinian patients. Looking forward, future studies on a larger number of patients could precisely highlight the genotype-phenotype association among FMF patients.

Detection of a rare variant in PSTPIP1 through three generations in a family with an initial diagnosis of FMF/MKD-overlapping phenotype

OBJECTIVE

The presence of FMF cases without MEFV (MEFV innate immunity regulator, pyrin) pathogenic variants led us to search for other genes' involvement in the disease development. Here, we describe the presence of genetic heterogeneity in a three-generation family with an FMF/mevalonate kinase deficiency (MKD)-overlapping phenotype without MEFV/MVK (mevalonate kinase) pathogenic variants.

METHOD

Targeted sequencing revealed a rare, fully penetrant variant in PSTPIP1 (p.Arg228Cys, rs781341816). Computational stability analyses of PSTPIP1 protein were performed. PSTPIP1-pyrin protein interaction was examined by immunoprecipitation and immunoblotting in peripheral blood mononuclear cells (PBMCs) of patients and healthy controls. PBMCs were cultured, and inflammation was induced by LPS+ATP treatment, followed by protein level measurements of caspase-1, IL1ß, pyrin and PSTPIP1 in cell lysates and mature caspase-1 and mature IL1ß in supernatants.

RESULTS

The conserved, rare (GnomAD, 0.000028) PSTPIP1 p.Arg228Cys variant, previously reported in ClinVar as a variant with uncertain significance, showed complete penetrance in the family presenting an autosomal dominant pattern. Computational analyses showed a potentially destabilizing effect of the variant on PSTPIP1 protein. Accordingly, PSTPIP1-pyrin interaction was increased in patients harboring the variant, which resulted in elevated levels of mature caspase-1 and IL1ß in the inflammation-induced patient samples.

CONCLUSIONS

Unlike previously described cases with pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA)-associated PSTPIP1 variants, our patients with the p.Arg228Cys variant presented with an FMF/MKD-overlapping phenotype. As additional data on the genetic heterogeneity in the variable clinical spectrum of autoinflammatory syndromes, we suggest that the p.Arg228Cys variant in PSTPIP1 is related to inflammation responses through strong PSTPIP1-pyrin interaction and pyrin inflammasome activation.

Genetic and Epigenetic Regulation of MEFV Gene and Their Impact on Clinical Outcome in Auto-Inflammatory Familial Mediterranean Fever Patients

Epigenetic modifications play a pivotal role in autoimmune/inflammatory disorders and could establish a bridge between personalized medicine and disease epidemiological contexts. We sought to investigate the role of epigenetic modifications beside genetic alterations in the MEFV gene in familial Mediterranean fever (FMF). The study comprised 63 FMF patients diagnosed according to the Tel Hashomer criteria: 37 (58.7%) colchicine-responders, 26 (41.3%) non-responders, and 19 matched healthy controls. MEFV mutations were detected using a CE/IVD-labeled 4-230 FMF strip assay. DNA methylation of MEFV gene exon 2 was measured using bisulfite modification and related to pyrin level, phenotypic picture, MEFV mutations, disease severity, serum amyloid A (SAA), CRP, ESR, disease severity, and colchicine response. Our results showed that FMF patients exhibited significantly higher methylation percentage (p < 0.001) and lower pyrin levels (p < 0.001) compared to the control. The MEFV gene M694I mutation was the most commonly reported mutation (p < 0.004). High methylation percentage of the MEFV exon 2 and low pyrin concentration were correlated with disease severity, high SAA, ESR levels, H-pylori, and renal calculi. In conclusion, this study highlights the relation between high methylation percentage, reduced pyrin level, and different biomarkers in FMF, which underscores their role in the pathogenesis of FMF and could be considered as potential therapeutic targets.

Spectrum of auto-inflammatory diseases in Morocco: a monocentric experience

Objective

Auto-inflammatory diseases (AIDs) result from mutations in genes of the innate immune system leading to periodic multisystemic inflammation. We aimed to describe the clinical, biological and molecular features (when available) and outcomes of Moroccan patients with AIDs.

Methods

Patient data were collected retrospectively and analysed over a 13-year period.

Results

Among 30 patients, 60% had FMF, 16% mevalonate kinase deficiency (MKD) and 24% other AIDs. The mean age at first consultation was 6.9 years, and the mean diagnostic delay was 3 years. Consanguinity was reported in 16 cases. IgA vasculitis was associated with 33% of FMF patients, in whom the main clinical features were fever (88.8%), abdominal pain (100%), arthralgias (88.8%) and arthritis (50%), and the most frequent mutation was M694V (66%). All FMF patients were treated with colchicine. Most MKD patients were confirmed by elevated urinary mevalonic acid levels, and four of five MKD patients received targeted therapy. Chronic recurrent osteomyelitis patients were confirmed by radiological and histological analysis. Two cases of Marshall syndrome were diagnosed according to validated criteria. A case of familial pustular psoriasis was diagnosed based on histological analysis and a patient with Muckle-Wells syndrome by clinical features. The outcome was favourable in 76%, partial in 13%, and three deaths were reported.

Conclusion

FMF and MKD are the most reported diseases. AIDs are probably underestimated because they are unknown to clinicians. The aim of this work is to raise awareness among paediatricians about AIDs and create a network for best practice.

Musculoskeletal and neurological manifestations in a cohort of Egyptian Familial Mediterranean fever patients: genotype-phenotype correlation

Background

Familial Mediterranean Fever (FMF) is a periodic auto-inflammatory disease with multiple systemic manifestations. This study aims to describe the various musculoskeletal and neurological manifestations in a cohort of Egyptian FMF patients and to evaluate their relation to the different Mediterranean fever gene (MEFV) mutations.

Results

This study involved 145 FMF patients, of them 62.1% were females and 31.7% were of the pediatric age. All involved patients had homozygous MEFV gene mutation. The presenting manifestation in 71.9% of these patients was abdominal pain followed by musculoskeletal manifestations in 35.2% of them. 38.6 % of the involved patients had arthritis during the period of follow-up. Monoarthritis was the most frequent pattern of arthritis. Arthralgia was present in 96.6% of the studied patients. Myalgia was present in 19.3% of the studied patients especially involving the lower limb muscles with one case of protracted febrile myalgia. Neurological manifestations were present in about 86.9 % of patients with vertigo, paresthesia, and seizures as the most common. Five major MEFV gene mutations were found in most of the studied patients (135 patients): M694V, M680I, E148Q, V726A, and M694I. When a comparative study was done between these five major mutations according to the age of onset of the symptoms, different musculoskeletal and neurological manifestations, ESR, serum amyloid level and dose of colchicine, no statistical difference was found.

Conclusion

Musculoskeletal manifestation is the second most common presenting symptom in a cohort of Egyptian FMF patients after abdominal pain. Arthralgia is the most frequent musculoskeletal manifestation while monoarthritis of the knee or ankle joint is the most common pattern of arthritis in FMF patients. Vertigo, paresthesia, and seizures are the most frequent neurological manifestations. Musculoskeletal manifestations, neurological manifestations, serum amyloid level, and dose of colchicine are not related to the type of the genetic mutation in this cohort.

Spectrum of MEFV gene mutations in 4,256 familial Mediterranean fever patients from Iran: a comprehensive systematic review

Background

Familial Mediterranean fever (FMF), known as a disease with a high prevalence rate among Armenian, Turkish, Jewish, and Arab descent populations, occurs as a result of pathogenic variants in mediterranean fever (MEFV) gene. The aim of this study was to review the spectrum and frequency of MEFV gene mutations reported among Iranian FMF patients.

Methods

After performing a systematic review of the literature and implementation of inclusion and exclusion criteria, 16 articles published between 2004 and 2020, involving 4,256 Iranian FMF patients, were included.

Results

A total of 38 different MEFV gene mutations were identified. The most common mutations among Iranian FMF patients were: p.M694V (c.2080A > G) (20.27%), p.E148Q (c.442G > C) (10.27%), p.V726A (c.2177T > C) (8.24%), p.M680I (both c.2040G > C and c.2040G > A) (7.20%), p.R761H (c.2282G > A) (2.1%), and p.M694I (c.2082G > A) (2. 1%). The frequencies of these mutations were significantly different in different parts of the country.

Conclusions

The ranks and frequencies of p.M694V, p.E148Q, p.V726A, p.M680I, and p.M694I in our population were closer to those observed in the Mediterranean countries, especially in the Middle Eastern Arab populations. Although some comprehensive studies have been performed on Azeri Turkish patients living in northwestern Iran, studies in other areas, especially in eastern Iran, have been very limited. One reason for this observation could be due to the low frequency of FMF patients in those areas. Regardless of the reason for this, the exact spectrum and frequency of MEFV gene mutations in Iranian FMF patients remain unclear. Therefore, comprehensive future studies in different parts of the country are recommended.

Deep Dive Into Familial Mediterranean Fever in a Child Without Fever

This case report entails the details of a 12-year-old Egyptian boy who had recurrent episodes of shortness of breath, ascites, and pericardial effusions starting at the age of 10, returning with worsening symptoms in April of 2020. The lab findings indicated a critically elevated C-reactive protein (CRP) of 107.2 mg/L; a clinically notable inflammation process was festering. This case was all the more interesting as this boy did not present with a fever, making the diagnosis a difficult one. Nonetheless, genetic Mediterranean fever (MEFv) and polymerase chain reaction (PCR) testing confirmed the diagnosis of familial MEFv. Steroids and colchicine-salicylate decreased the frequency of the attacks and are now on half a dose of colchicine to keep his symptoms at bay. What we see here is the risk-to-benefit ratio of the therapeutic use of colchicine in children outweighs potential side effects such as nausea, vomiting, abdominal pain, diarrhea, kidney or liver failure. However, further research is needed to access better long-term treatment plans. Another key takeaway point that can be highlighted in this case is that the patient does not need to be febrile to diagnose FMF.

Presentation of a new mutation in FMF and evaluating the frequency of distribution of the MEFV gene mutation in our region with clinical findings

Familial Mediterranean Fever (FMF), which is an autosomal recessive disease characterized by recurrent self-limiting fever, peritonitis, pleuritis, arthritis and erysipelas-like erythemas, has been common among ethnic groups such as Turkish, Armenian, Arabic and Jewish. The clinical presentation is caused by mutations in the MEFV gene encoding the Pyrin protein. In this study, we aimed to present a new mutation that has not been previously defined from the mutations in the MEFV gene which is responsible for the genetic pathology of familial Mediterranean fever and to evaluate the frequency of distribution of the MEFV gene mutation among different ethnic groups living in our region. In present retrospective study, a total of 2639 clinically suspected FMF patients who were referred to Hatay Mustafa Kemal University Hospital between 2010 and 2017 were recorded. MEFV gene mutations were observed using DNA sequence analysis. MEFV mutations were found in 2079 of the 2639 patients (78.7%) Among these patients 184 (6.97%) were homozygous, while 1365 (51.72%) were heterozygous. The most frequently observed mutation was R202Q (1319, 19.55%) followed by E148Q (n = 476, 7.05%), M694V (n = 439, 6.51%), V726A (n = 146, 2.16%) and M680I (n = 135, 2%). In a case clinically diagnosed as FMF, a new mutation called S145G (p. Ser145Gly, c.433A > G) was identified in exon 2 of the MEFV gene. Besides, addition of a new pathogenic MEFV variant to the literature, the relationship between the FMF clinic and homozygous form of R202Q, which was previously considered as a polymorphism, was highlighted.

Differential mutational profiles of familial Mediterranean fever in North Africa

Familial Mediterranean fever (FMF) is a recessive autoinflammatory disease, mainly occurring in the eastern Mediterranean. In these populations, the five FMF founder mutations are differently distributed. In Algeria, the FMF-causing variants remain poorly explored. This retrospective study aims to report the mutational profile of Algerian FMF patients and to compare it with North African FMF patients. One hundred eighty-three unrelated patients clinically suspected of FMF were recruited from various Algerian hospitals (2007-2015) and tested for mutations in exon 10 of MEFV gene. Molecular analysis identified 144 mutant alleles among 87 of 183 patients (47.5%). p.M694I was the most prevalent pathogenic allele, accounting for 63.2% of mutant alleles, followed by p.M694V and p.M680I occurring with a same frequency (14.5%). Others, p.A744S (6.2%) and p.I692del (1.3%), are less frequent. Interestingly, p.M694I was the most recurrent in patients with renal AA-amyloidosis. Our results provide the first genetic data on FMF in Algeria, demonstrating the predominance of p.M694I and the absence of p.V726A, compared to other North African countries (Morocco, Tunisia, and Egypt). In conclusion, North African FMF patients display differential mutational profiles that may result from the difference in ethnic origin and the genetic heterogeneity among these populations.

Spectrum of MEFV Variants and Genotypes among Clinically Diagnosed FMF Patients from Southern Lebanon

Background: Familial Mediterranean Fever (FMF) is an autosomal recessive auto-inflammatory disease characterized by pathogenic variants in the MEFV gene, with allele frequencies greatly varying between countries, populations and ethnic groups. Materials and methods: In order to analyze the spectrum of MEFV variants and genotypes among clinically diagnosed FMF patients from South Lebanon, data were collected from 332 participants and 23 MEFV variants were screened using a Real-Time PCR Kit. Results: The mean age at symptom onset was 17.31 ± 13.82 years. The most prevalent symptoms were abdominal pain, fever and myalgia. MEFV molecular analysis showed that 111 patients (63.79%) were heterozygous, 16 (9.20%) were homozygous, and 47 (27.01%) carried two variants or more. E148Q was the most encountered variant among heterozygous subjects. E148Q/M694V was the most frequent in the compound heterozygous/complex genotype group, while M694I was the most common among homozygous patients. Regarding allele frequencies, M694V was the most common variant (20.7%), followed by E148Q (17.1%), V726A (15.7%) and M694I (13.2%). Conclusion: The high percentage of heterozygous patients clinically diagnosed as FMF highlights the pseudo-dominant transmission of the disease in Lebanon and emphasizes the importance of molecular testing for a more accurate diagnosis and better management and treatment of FMF.

Familial Mediterranean Fever without Fever

Familial Mediterranean fever (FMF) is an autosomal recessive hereditary disease commonly observed around the Mediterranean basin presenting as recurrent febrile episodes. We herein describe a Japanese case of genetically-confirmed FMF, in which fever was lacking during attacks. An otherwise healthy 34-year-old man presented with frequent episodes of abdominal pain, which resolved spontaneously. During the attacks, the patient was afebrile, but the inflammatory marker levels in his blood were increased. Abdominal CT demonstrated enhancement of the jejunal membrane. After the initiation of colchicine therapy, the patient experienced no attacks for more than one year. The diagnosis of FMF was confirmed by a genetic analysis.

Structural and Functional Analysis of Mutated Human Pyrin B30.2 Domain

Background:

Familial Mediterranean Fever (FMF) is a prototypical hereditary autoinflammatory disease affecting principally Mediterranean populations and characterized by recurrent frequent fever and inflammation. The disease is essentially caused by inherited mutations in the MEFV gene which encodes pyrin protein. The reported mutations are mostly located on the B30.2 domain in the C-terminal end of the protein.

Objective:

The present study reports a structural comparison of the five most common mutated structures including M694V, V726A, M694I, R761H, and M680I. The aim of this study was to determine the structural and functional disorders caused by the mutations in the human pyrin protein.

Results:

The comparison revealed that all mutations make overall changes in the structure of the domain. Further, the effects of these mutations on structural and molecular behavior of the B30.2 domain were compared with the native structure using MD simulation by GROMACS software. The results revealed that all the studied mutants have a destabilizing effect on the protein structure. Additionally, analyzing the projection of the motions of the proteins in phase space demonstrates high rigidity of the mutated structures in comparison with the native protein.

Conclusion:

The results of simulations elucidate how the mutations affect the physiological functioning of the pyrin B30.2 domain and cause the occurrence of the FMF disease.

Pattern and diagnostic evaluation of systemic autoinflammatory diseases other than familial Mediterranean fever among Arab children: a multicenter study from the Pediatric Rheumatology Arab Group (PRAG)

To define the spectrum and phenotypic characteristics of systemic autoinflammatory diseases (SAIDs) other than familial Mediterranean fever (FMF) in Arab children and to delineate diagnostic evaluation. Data retrospectively collected on patients with clinical and/or genetically proven SAIDs other than FMF at 10 tertiary Arab pediatric rheumatology clinics from 1990 to 2018. The collected data comprised the clinical findings and diagnostic evaluation including genetic testing, the provided treatment and the accrual damage related to SAIDs. A total of 144 patients (93 female) with a median age at onset of 2.5 (range 0.1-12) years were enrolled. The initial diagnosis was inaccurate in 49.3%. Consanguinity rate among parents was 74.6%. The median time-to-diagnosis for all SAIDs was 2.5 (range 0.1-10) years. There were 104 patients (72.2%) with a confirmed diagnosis and 40 patients with suspected SAIDs. Seventy-two had monogenic and 66 patients with multifactorial SAIDs while six patients had undifferentiated SAIDs. The most frequent monogenic SAIDs were LACC1 mediated monogenic disorders (n = 23) followed by CAPS (12), TRAPS (12), HIDS (12), and Majeed's syndrome (6). The most frequent multifactorial SAIDs was CRMO (34), followed by PFAPA (18), and early onset sarcoidosis (EOS) (14). Genetic analysis was performed in 69 patients; 50 patients had genetically confirmed disease. Corticosteroid used for 93 patients while biologic agents for 96 patients. Overall, growth failure was the most frequent accrual damage (36%), followed by cognitive impairment (13%). There were three deaths because of infection. This study shows a heterogenous spectrum of SAIDs with a high number of genetically confirmed monogenic diseases; notably, LACC1 associated diseases. Hopefully, this work will be the first step for a prospective registry for SAIDs in Arab countries.