[Challenges in diagnosing familial Mediterranean fever: exploring atypical clinical features. Clinical case].

This clinical case series presents descriptions of 3 patients with familial Mediterranean fever (FMF) who have atypical manifestations and abnormal inheritance mechanisms in terms of Gregor Mendel's laws. Although molecular genetic testing can help with disease diagnosis, it is not always conclusive. The primary need for genetic testing in atypical cases is to explain the mechanism of inflammation and to select the optimal therapy. These clinical observations demonstrate the changes in the spectrum of phenotypic manifestations of FMF in the context of the widespread introduction of molecular genetic methods.

Clinical Associations of E148Q Heterozygosity: What to Expect From E148Q?

OBJECTIVE: The exact effects of MEFV variants on inflammation are still under investigation, and reports on variants of unknown significance, particularly the E148Q variant, have been conflicting. Therefore, this study aims to investigate patients exhibiting E148Q heterozygosity, focusing on diagnoses and disease courses to assist physicians in interpreting the variant. METHODS: Data of pediatric patients presenting to the Pediatric Rheumatology clinic between November 2016 and September 2023, exhibiting only E148Q heterozygosity in MEFV gene analysis, were extracted. Patients who were lost before 9 months of follow-up have been excluded to ensure the completion of initial diagnostic tests and evaluations. RESULTS: Among the 119 patients with E148Q variant, the diagnoses were as follows: healthy, 51.3%; IgA vasculitis, 10.1%; Familial Mediterranean Fever (FMF), 7.6%; Periodic fever, Aphtous stomatitis, Pharyngitis, Adenitis (PFAPA), 6.7%; and other diagnoses, 19.3%. IgA vasculitis patients experienced articular, gastrointestinal, and renal involvement at rates of 91.7%, 58.3%, and 16.7%, respectively. Complete response, partial response, and no response to colchicine were 37.5%, 12.5%, and 50%, respectively, in PFAPA patients. All FMF patients responded to colchicine treatment resulting in reduced mean FMF episode counts in 6 months from 3.22 ± 0.92 to 0.56 ± 0.52. CONCLUSIONS: The E148Q variant may amplify inflammation and modify disease courses. Patients with the E148Q variant experiencing typical FMF episodes should receive colchicine, but clinicians should exercise caution regarding alternative diagnoses. Additionally, the E148Q variant may increase acute phase reactants and disease severity in IgA vasculitis. However, to reach definitive conclusions on its treatment-modifying role in PFAPA, universal diagnosis and treatment response criteria should be adopted.

How do gene mutation diversity and disease severity scoring affect physical capacity and quality of life in children/adolescents with Familial Mediterranean Fever?

OBJECTIVES: The aim of this study is to examine how gene mutation diversity and disease severity affect physical capacity and quality of life in children/adolescents with Familial Mediterranean Fever (FMF). METHODS: Eighty children/adolescents (42 female, 38 male) diagnosed with FMF according to Tell-Hashomer diagnostic criteria were included in this study. Disease severity score (PRAS), running speed and agility and strength subtests of Bruininks-Oseretsky Test of Motor Proficiency Second Edition Short Form (BOT-2 SF), Physical Activity Questionnaire, Pediatric Quality of Life Inventory 3.0 Arthritis Module (PedsQL) was used for evaluation. Participants were divided into 2 groups as M694V and other mutations according to MEFV gene mutation and were divided into 3 groups as mild, moderate and severe according to PRAS. RESULTS: When the data were compared between groups; in terms of gene mutation, a significant difference was observed in treatment subtest of PedsQL-parent form in favor of the M694V gene mutation group (p<0.05). In terms of PRAS, significant difference was seen in the pain, treatment subtests and total score of the PedsQL-child form, and in the pain, treatment, worry subtests and total score of the PedsQL-parent form in favor of the mild group (p<0.05). CONCLUSIONS: MEFV gene mutations in children and adolescents with FMF did not differ on physical capacity and quality of life. PRAS was not effective on physical parameters, but quality of life decreased as the severity score increased. Encouraging children/adolescents with FMF to participate in physical activity and to support them psychosocially can be important to improve their quality of life.

Comparison of Clinical and Genetic Characteristics of Familial Mediterranean Fever Patients Among Adult Age Groups.

Familial mediterranean fever (FMF) is a genetic autoinflammatory disease typically diagnosed in childhood. In this study, we aimed to investigate the demographic, clinical, and genetic characteristics of patients aged 18 years and older who were diagnosed with FMF. Patients diagnosed with FMF between 2014 and 2022 at Karadeniz Technical University Faculty of Medicine Hospital were included in the study. Patients were divided into 2 groups based on the age of disease onset. Group I included patients with adult-onset (ages 18-40), while group II comprised patients with late onset (ages 40 and above). Subsequently, the 2 groups were compared. A total of 150 patients with a mean age of 32 (18-79) were included in the study. There were 116 patients in group I and 34 (22.7%) in group II. The most common presenting complaint was abdominal pain (91.3%), and the most prevalent complication was amyloidosis (4.7%). No significant differences were observed between age groups regarding clinical findings and symptoms. The most frequent homozygous mutations were M694V (9.3%) and R202Q (1.8%), while the heterozygous mutations were M694V (37.3%) and R202Q (35.5%), respectively. The rate of M694V gene positivity in the adult-onset group was significantly higher compared to the lateonset group (52.9% and 25%, respectively, P = .020). There does not appear to be a significant difference in clinical signs and symptoms between adult-onset and late-onset FMF patients. The higher rate of M694V gene positivity in the adult-onset group suggests that the M694V mutation may be responsible for the early expression of the disease.

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.

Generation of iPSCs from a Patient with the M694V Mutation in the MEFV Gene Associated with Familial Mediterranean Fever and Their Differentiation into Macrophages.

Familial Mediterranean fever (FMF) is a systemic autoinflammatory disorder caused by inherited mutations in the MEFV (Mediterranean FeVer) gene, located on chromosome 16 (16p13.3) and encoding the pyrin protein. Despite the existing data on MEFV mutations, the exact mechanism of their effect on the development of the pathological processes leading to the spontaneous and recurrent autoinflammatory attacks observed in FMF, remains unclear. Induced pluripotent stem cells (iPSCs) are considered an important tool to study the molecular genetic mechanisms of various diseases due to their ability to differentiate into any cell type, including macrophages, which contribute to the development of FMF. In this study, we developed iPSCs from an Armenian patient with FMF carrying the M694V, p.(Met694Val) (c.2080A>G, rs61752717) pathogenic mutation in exon 10 of the MEFV gene. As a result of direct differentiation, macrophages expressing CD14 and CD45 surface markers were obtained. We found that the morphology of macrophages derived from iPSCs of a patient with the MEFV mutation significantly differed from that of macrophages derived from iPSCs of a healthy donor carrying the wild-type MEFV gene.

Elucidating the molecular landscape of tendinitis: the role of inflammasome-related genes and immune interactions.

Tendinitis, characterized by the inflammation of tendons, poses significant challenges in both diagnosis and treatment due to its multifaceted etiology and complex pathophysiology. This study aimed to dissect the molecular mechanisms underlying tendinitis, with a particular focus on inflammasome-related genes and their interactions with the immune system. Through comprehensive gene expression analysis and bioinformatics approaches, we identified distinct expression profiles of inflammasome genes, such as NLRP6, NLRP1, and MEFV, which showed significant correlations with immune checkpoint molecules, indicating a pivotal role in the inflammatory cascade of tendinitis. Additionally, MYD88 and CD36 were found to be closely associated with HLA family molecules, underscoring their involvement in immune response modulation. Contrary to expectations, chemokines exhibited minimal correlation with inflammasome genes, suggesting an unconventional inflammatory pathway in tendinitis. Transcription factors like SP110 and CREB5 emerged as key regulators of inflammasome genes, providing insight into the transcriptional control mechanisms in tendinitis. Furthermore, potential therapeutic targets were identified through the DGidb database, highlighting drugs that could modulate the activity of inflammasome genes, offering new avenues for targeted tendinitis therapy. Our findings elucidate the complex molecular landscape of tendinitis, emphasizing the significant role of inflammasomes and immune interactions, and pave the way for the development of novel diagnostic and therapeutic strategies.

The significance of carrying MEFV variants in symptomatic and asymptomatic individuals.

Familial Mediterranean fever (FMF) is an autoinflammatory disease characterized by recurrent attacks of fever, serositis (peritonitis, pleuritis, or synovitis), and erysipelas-like erythema. Genetic variants in the MEFV gene are associated with this disease. Familial Mediterranean fever is considered an autosomal recessive disease. However, in Middle Eastern countries, a third of the patients expressing FMF manifestations, carry a single mutation only. Moreover, some cases of pure dominant inheritance linked to specific single MEFV variants have also been described. This complex inheritance of MEFV-associated inflammatory diseases poses a serious challenge when interpreting the results of genetic testing in patients having recurrent fever syndromes. In addition, in certain situations, asymptomatic individuals may be incidentally found to carry MEFV variants. These cases pose the question of their exact diagnosis and whether they should be treated. Previous studies have focused on genetic results interpretations among symptomatic patients. In the current article, we would like to elaborate on the genetic interpretation in cases of symptomatic individuals suspected to have FMF and on asymptomatic individuals carrying MEFV variants. We aim to assist physicians unfamiliar with FMF to cope with genetic results interpretation when facing symptomatic and asymptomatic individuals carrying MEFV variants and suggest a management plan accordingly.

Next-generation sequencing based newborn screening and comparative analysis with MS/MS.

BACKGROUND: Newborn screening (NBS), such as tandem mass spectrometry (MS/MS), may yield false positive/negative results. Next-generation sequencing (NGS) has the potential to provide increased data output, efficiencies, and applications. This study aimed to analyze the types and distribution of pathogenic gene mutations in newborns in Huzhou, Zhejiang province, China and explore the applicability of NGS and MS/MS in NBS. METHODS: Blood spot samples from 1263 newborns were collected. NGS was employed to screen for pathogenic variants in 542 disease-causing genes, and detected variants were validated using Sanger sequencing. Simultaneously, 26 inherited metabolic diseases (IMD) were screened using MS/MS. Positive or suspicious samples identified through MS/MS were cross-referenced with the results of NGS. RESULTS: Among all newborns, 328 had no gene mutations detected. NGS revealed at least one gene mutation in 935 newborns, with a mutation rate of 74.0%. The top 5 genes were FLG, GJB2, UGT1A1, USH2A, and DUOX2. According to American College of Medical Genetics guidelines, gene mutations in 260 cases were classified as pathogenic or likely pathogenic mutation, with a positive rate of 20.6%. The top 5 genes were UGT1A1, FLG, GJB2, MEFV, and G6PD. MS/MS identified 18 positive or suspicious samples for IMD and 1245 negative samples. Verification of these cases by NGS results showed no pathogenic mutations, resulting in a false positive rate of 1.4% (18/1263). CONCLUSION: NBS using NGS technology broadened the range of diseases screened, and enhanced the accuracy of diagnoses in comparison to MS/MS for screening IMD. Combining NGS and biochemical screening would improve the efficiency of current NBS.

Predicting genetic risk factors for AA amyloidosis in Algerian patients with familial Mediterranean fever.

Renal amyloid-associated (AA) amyloidosis is a harmful complication of familial Mediterranean fever (FMF). Its occurrence involves polymorphisms and mutations in the Serum Amyloid A1 (SAA1) and Mediterranean Fever (MEFV) genes, respectively. In Algeria, the association between SAA1 variants and FMF-related amyloidosis was not investigated, hence the aim of this case-control study. It included 60 healthy controls and 60 unrelated FMF patients (39 with amyloidosis, and 21 without amyloidosis). All were genotyped for the SAA1 alleles (SAA1.1, SAA1.5, and SAA1.3), and a subset of them for the - 13 C/T polymorphism by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Comparisons between genotype and allele frequencies were performed using Chi-square and Fisher tests. The SAA1.1/1.1 genotype was predominant in amyloid FMF patients, compared to non-amyloid FMF patients (p = 0.001) and controls (p < 0.0001). SAA1.1/1.5 was higher in non-amyloid patients (p = 0.0069) and in controls (p = 0.0082) than in patients with amyloidosis. Bivariate logistic regression revealed an increased risk of AA amyloidosis with three genotypes, SAA1.1/1.1 [odds ratio 7.589 (OR); 95% confidence interval (CI): 2.130-27.041] (p = 0.0018), SAA1.1/1.3 [OR 5.700; 95% CI: 1.435-22.644] (p = 0.0134), and M694I/M694I [OR 4.6; 95% CI: 1.400-15.117] (p = 0.0119). The SAA1.1/1.5 genotype [OR 0.152; 95% CI: 0.040-0.587] (p = 0.0062) was protective against amyloidosis. In all groups, the - 13 C/C genotype predominated, and was not related to renal complication [OR 0.88; 95% CI: 0.07-10.43] (p = 0.915). In conclusion, in contrast to the - 13 C/T polymorphism, the SAA1.1/1.1, SAA1.1/1.3 and M694I/M694I genotypes may increase the risk of developing renal AA amyloidosis in the Algerian population.

Epigenetic insights into Familial Mediterranean Fever: Increased RGS10 expression and histone modifications accompanies inflammation in familial Mediterranean fever disease.

BACKGROUND: Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disease characterized by recurring fever, erythema, joint pain, and abdominal discomfort during acute episodes. While FMF patients typically share MEFV gene mutations, they display varying clinical manifestations, suggesting the involvement of modifying genes, epigenetic mechanisms, or environmental factors. G protein regulator signal 10 (RGS10), a member of the RGS protein family, exhibits anti-inflammatory effects in autoinflammatory diseases. There are no studies on the role of plays in FMF pathogenesis or histone modification in FMF. AIMS: This study aimed to shed light on the epigenetic regulation of FMF from several perspectives. The relationship between RGS10 DNA hypermethylation in FMF clinical parameters and the regulation of 22 histone modifications were examined in FMF attack patients and the control group. METHODS: Sixty FMF (remission/attack) and thirty healthy individuals were included in the study. First, RNA was isolated from the blood of patients/controls, and the expression of RGS10 was examined. Then, DNA was isolated from the patients, and gene-specific hypermethylation was investigated using the bisulfite conversion method. Finally, histone extraction was performed for FMF patients and controls and 22 histone H3 modifications were determined. In addition, using ADEX bioinformatics tools, RGS10 expression and methylation profiles were detected in different autoinflammatory diseases. RESULTS: This study indicate that RGS10 expression decreased in attack-free/attack patients than control, attributed to DNA methylation. In addition, there were a positive correlation between FMF patients and attack, WBC, neutrophil, MCHC and MPV. Moreover, higher H3K4 me3, H3K9 me2, and H3K14ac levels were observed in patients with FMF attacks. This research also showed a consistent decrease in RGS10 expression in patients with SjS, SSc, and T1D compared with controls. I also obtained five prognosis-related CpGs (cg17527393, cg19653161, cg20445950, cg18938673 and cg13975098) of RGS10 in patients with SjS, RA, SSc, SLE and T1D. CONCLUSION: The present study provides insights into the complex relationship between RGS10, epigenetic modifications, and immune responses in FMF. While RGS10 may initially enhance immune responses, genetic mutations and epigenetic changes associated with FMF acute episode may override this regulatory effect, resulting in increased inflammation and clinical symptoms. Moreover, our study revealed elevated levels of specific histone modifications in the context of FMF, suggesting significant epigenetic changes that could contribute to the disease pathogenesis. Understanding these associations opens new avenues for research and potential therapeutic interventions, potentially involving epigenetic therapies targeting histone modifications.

Updates on the role of epigenetics in familial mediterranean fever (FMF).

Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disease caused by mutations in the MEFV (MEditerranean FeVer) gene that affects people originating from the Mediterranean Sea. The high variability in severity and clinical manifestations observed not only between ethnic groups but also between and within families is mainly related to MEFV allelic heterogeneity and to some modifying genes. In addition to the genetic factors underlying FMF, the environment plays a significant role in the development and manifestation of this disease through various epigenetic mechanisms, including DNA methylation, histone modification, and noncoding RNAs. Indeed, epigenetic events have been identified as an important pathophysiological determinant of FMF and co-factors shaping the clinical picture and outcome of the disease. Therefore, it is essential to better understand the contribution of epigenetic factors to autoinflammatory diseases, namely, FMF, to improve disease prognosis and potentially develop effective targeted therapies. In this review, we highlight the latest updates on the role of epigenetics in FMF.

Interrupting an IFN-γ-dependent feedback loop in the syndrome of pyogenic arthritis with pyoderma gangrenosum and acne.

OBJECTIVES: To study the molecular pathogenesis of PAPA (pyogenic arthritis, pyoderma gangrenosum and acne) syndrome, a debilitating hereditary autoinflammatory disease caused by dominant mutation in PSTPIP1. METHODS: Gene knock-out and knock-in mice were generated to develop an animal model. THP1 and retrovirally transduced U937 human myeloid leukaemia cell lines, peripheral blood mononuclear cells, small interfering RNA (siRNA) knock-down, site-directed mutagenesis, cytokine immunoassays, coimmunoprecipitation and immunoblotting were used to study inflammasome activation. Cytokine levels in the skin were evaluated by immunohistochemistry. Responsiveness to Janus kinase (JAK) inhibitors was evaluated ex vivo with peripheral blood mononuclear cells and in vivo in five treatment-refractory PAPA patients. RESULTS: The knock-in mouse model of PAPA did not recapitulate the human disease. In a human myeloid cell line model, PAPA-associated PSTPIP1 mutations activated the pyrin inflammasome, but not the NLRP3, NLRC4 or AIM2 inflammasomes. Pyrin inflammasome activation was independent of the canonical pathway of pyrin serine dephosphorylation and was blocked by the p.W232A PSTPIP1 mutation, which disrupts pyrin-PSTPIP1 interaction. IFN-γ priming of monocytes from PAPA patients led to IL-18 release in a pyrin-dependent manner. IFN-γ was abundant in the inflamed dermis of PAPA patients, but not patients with idiopathic pyoderma gangrenosum. Ex vivo JAK inhibitor treatment attenuated IFN-γ-mediated pyrin induction and IL-18 release. In 5/5 PAPA patients, the addition of JAK inhibitor therapy to IL-1 inhibition was associated with clinical improvement. CONCLUSION: PAPA-associated PSTPIP1 mutations trigger a pyrin-IL-18-IFN-γ positive feedback loop that drives PAPA disease activity and is a target for JAK inhibition.

Unraveling the genome: Familial Mediterranean fever.

ABSTRACT: Familial Mediterranean fever (FMF) is an inherited, autoinflammatory disease with a high prevalence in Middle Eastern and Mediterranean populations including Turks, Iranian, Spanish, Sephardic Jews, Arabs, and other Mediterranean ethnic groups. Autoinflammatory diseases are genetically predetermined disorders with multisystem effects primarily caused by defects in innate immunity. Although primarily known for an autosomal recessive mode of inheritance, there are increasing case reports associated with single Mediterranean fever (MEFV) mutation or dominant transmission. There have been over 300 variants identified in the MEFV gene; however, roughly 9-11 variants are responsible for the phenotypical expression seen with FMF. Symptoms include recurrent episodes of fever of unknown origin, abdominal, chest, or joint pain because of serosal inflammation. Persistent elevations in serum amyloid A can lead to complications like renal amyloidosis, kidney dysfunction, and end-stage kidney disease. Familial Mediterranean fever is diagnosed clinically using the Tel-Hashomer criteria and confirmed through genetic testing. Treatment includes initiation of colchicine with the goal of stopping attacks and preventing renal dysfunction and end-stage kidney disease. Genetic testing helps to identify the specific mutation allowing the provider to create a patient-specific treatment plan, monitor for complications such as renal amyloidosis, and enhance knowledge on the genetic heterogeneity and possible epigenetic factors.

Pyrin Inflammasome Activation Defines Colchicine-Responsive SURF Patients from FMF and Other Recurrent Fevers.

Syndrome of undifferentiated recurrent fever (SURF) is characterized by recurrent fevers, a lack of confirmed molecular diagnosis, and a complete or partial response to colchicine. Despite the clinical similarities to familial Mediterranean fever (FMF), the underlying inflammatory mechanisms of SURF are not yet understood. We here analyzed the in vitro activation of the pyrin inflammasome in a cohort of SURF patients compared to FMF and PFAPA patients. Peripheral blood mononuclear cells (PBMC) were collected from SURF (both colchicine-treated and untreated), FMF, PFAPA patients, and healthy donors. PBMC were stimulated ex vivo with Clostridium difficile toxin A (TcdA) and a PKC inhibitor (UCN-01), in the presence or absence of colchicine. The assembly of the pyrin inflammasome was evaluated by measuring the presence of apoptosis-associated Speck-like protein containing caspase recruitment domain (ASC) specks in monocytes using flow cytometry. IL-1ß secretion was quantified using an ELISA assay. No differences in TcdA-induced activation of pyrin inflammasome were observed among FMF, PFAPA, and healthy donors. Untreated SURF patients showed a reduced response to TcdA, which was normalized after colchicine treatment. In contrast to FMF, SURF patients, similar to PFAPA patients and healthy donors, did not exhibit pyrin inflammasome activation in response to UCN-01-mediated pyrin dephosphorylation. These data demonstrate that in vitro functional analysis of pyrin inflammasome activation can differentiate SURF from FMF and PFAPA patients, suggesting the involvement of the pyrin inflammasome in the pathophysiology of SURF.