Global epidemiology of Familial Mediterranean fever mutations using population exome sequences

Single Nucleotide Polymorphisms of the MEFV Gene E148Q Are Highly Associated With Disease Phenotype in Crohn's Disease

BACKGROUND

Single nucleotide polymorphisms (SNPs) of the MEFV gene may modify inflammatory bowel disease (IBD) activity. The prevalence of MEFV gene SNPs in IBD patients and their involvement in IBD pathophysiology remains unclear.

METHODS

We analyzed 12 MEFV gene SNPs in peripheral leukocytes of Japanese IBD patients (Crohn's disease [CD]: 69 patients, ulcerative colitis: 32 patients) by polymerase chain reaction using next-generation DNA sequencing and evaluated their prevalence and association with the disease characteristics. Inflammasome activity and mature interleukin (IL)-1β and IL-18 production were evaluated in peripheral blood mononuclear cells obtained from CD patients stimulated with lipopolysaccharides and adenosine triphosphate, and compared between those with and without the E148Q SNP. COL1A1 and HSP47 gene expression was analyzed in CCD-18Co cells costimulated with IL-1β and other inflammatory cytokines.

RESULTS

The prevalence of MEFV gene SNPs in IBD patients was similar to that in the human gene database. E148Q was the most common SNP. Compared with CD patients without E148Q, those with E148Q had a significantly greater frequency of the stricture phenotype, and their peripheral blood mononuclear cells exhibited significantly higher IL-1β and IL-18 levels and higher caspase-1 activity. IL-1β and IL-17A synergistically increased COL1A1 and HSP47 gene expression.

CONCLUSIONS

MEFV gene SNPs, including E148Q, modify the behavior of CD. IL-1β and IL-18 are produced through enhanced caspase-1 activity in monocytes of CD patients with E148Q. IL-1β promotes gene expression of fibrosis-related genes by cooperating with IL-17A in myofibroblasts. Therefore, E148Q might be a disease-modifying gene associated with the fibrostenosis phenotype in CD patients.

Next generation sequencing (NGS)-based approach to diagnosing Algerian patients with suspected inborn errors of immunity (IEIs)

The advent of next-generation sequencing (NGS) technologies has greatly expanded our understanding of both the clinical spectra and genetic landscape of inborn errors of immunity (IEIs). Endogamous populations may be enriched for unique, ancestry-specific disease-causing variants, a consideration that significantly impacts molecular testing and analysis strategies. Herein, we report on the application of a 2-step NGS-based testing approach beginning with targeted gene panels (TGPs) tailored to specific IEI subtypes and reflexing to whole exome sequencing (WES) if negative for Northwest Algerian patients with suspected IEIs. Our overall diagnostic yield of 57% is comparable to others broadly applying short-read NGS to IEI detection, but data from our localized cohort show some similarities and differences from NGS studies performed on larger regional IEI cohorts. This suggests the importance of tailoring diagnostic strategies to local demographics and needs, but also highlights ongoing concerns inherent to the application of genomics for clinical IEI diagnostics.

Rare, Overlooked, or Underappreciated Causes of Recurrent Abdominal Pain: A Primer for Gastroenterologists

Recurrent abdominal pain is a common reason for repeated visits to outpatient clinics and emergency departments, reflecting a substantial unmet need for timely and accurate diagnosis. A lack of awareness of some of the rarer causes of recurrent abdominal pain may impede diagnosis and delay effective management. This article identifies some of the key rare but diagnosable causes that are frequently missed by gastroenterologists and provides expert recommendations to support recognition, diagnosis, and management with the ultimate aim of improving patient outcomes.

＜Editors' Choice＞ Myelodysplastic syndrome with trisomy 8 presenting periodic fever and multiple MEFV gene variants outside exon 10: a case report

Myelodysplastic syndrome is associated with the development of autoinflammatory conditions, such as recurrent fever, polymyalgia, arthralgia, and erythema. Trisomy 8 is a common chromosomal abnormality in patients with myelodysplastic syndrome. Myelodysplastic syndrome with trisomy 8 involves autoinflammatory conditions, especially Behçet's disease-like symptoms with intestinal mucosal damage. MEFV variants, particularly those in exon 10, are pathogenic in familial Mediterranean fever, the most common autoinflammatory disease, presenting typical symptoms such as periodic fever and pleuritis/pericarditis/peritonitis. MEFV variants outside exon 10 are common in Japanese patients with familial Mediterranean fever and are associated with atypical symptoms, including myalgia and erythema. MEFV variants in myelodysplastic syndrome with trisomy 8 have rarely been investigated, although myelodysplastic syndrome with trisomy 8 might develop autoinflammatory conditions similar to those in familial Mediterranean fever. We encountered a 67-year-old man who had myelodysplastic syndrome with trisomy 8 and multiple MEFV variants outside exon 10. He presented with periodic fever, as well as chest/abdominal pain, myalgia, and erythema, although the symptoms did not fulfill the diagnostic criteria of familial Mediterranean fever. We discussed the possibility that these symptoms are modified by MEFV variants outside exon 10 in myelodysplastic syndrome with trisomy 8.

Immunogenic Potential of the Mediterranean Fever Gene in Patients with Coronavirus Disease: A Cross-Sectional Study

Background

In December 2019, an outbreak of pneumonia caused by the novel coronavirus disease 2019 (COVID-19) became a pandemic and caused a global health crisis. This study evaluates the immunogenic potential of the Mediterranean fever (MEFV) gene in patients with COVID-19.

Methods

A cross-sectional study was conducted from March to April 2020 in various COVID-19 referral centers in Ardabil, Iran. Blood samples of 50 hospitalized patients with confirmed COVID-19 were evaluated for MEFV gene mutation using the amplification refractory mutation system polymerase chain reaction (ARMS-PCR) and Sanger sequencing. Statistical analysis was performed using SPSS software, version 22.0.

Results

Mutations of the MEFV gene were found in 6 (12%) of the patients. All mutations were heterozygous, and no homozygous or compound heterozygous forms were detected. The total mutant allele frequency was 6% and the carrier rate was 12%. The most common allele of the MEFV variant was E148Q, detected in 3 (6%) patients. No mutant variant of the MEFV gene was detected in deceased patients. None of the mutation carriers had familial Mediterranean fever (FMF) symptoms or a family history of FMF.

Conclusion

MEFV gene mutations may have immunogenic potential in patients with COVID-19. A preprint version of this article has already been published at https://www.researchsquare.com/article/rs-69373/latest.pdf.

Identification of a Germline Pyrin Variant in a Metastatic Melanoma Patient With Multiple Spontaneous Regressions and Immune-related Adverse Events

The mechanisms underlying tumor immunosurveillance and their association with the immune-related adverse events (irAEs) associated with checkpoint inhibitor immunotherapies remain poorly understood. We describe a metastatic melanoma patient exhibiting multiple episodes of spontaneous disease regression followed by the development of several irAEs during the course of anti-programmed cell death protein 1 antibody immunotherapy. Whole-exome next-generation sequencing studies revealed this patient to harbor a pyrin inflammasome variant previously described to be associated with an atypical presentation of familial Mediterranean fever. This work highlights a potential role for inflammasomes in the regulation of tumor immunosurveillance and the pathogenesis of irAEs.

Whole-genome sequencing of 1,171 elderly admixed individuals from São Paulo, Brazil

As whole-genome sequencing (WGS) becomes the gold standard tool for studying population genomics and medical applications, data on diverse non-European and admixed individuals are still scarce. Here, we present a high-coverage WGS dataset of 1,171 highly admixed elderly Brazilians from a census-based cohort, providing over 76 million variants, of which ~2 million are absent from large public databases. WGS enables identification of ~2,000 previously undescribed mobile element insertions without previous description, nearly 5 Mb of genomic segments absent from the human genome reference, and over 140 alleles from HLA genes absent from public resources. We reclassify and curate pathogenicity assertions for nearly four hundred variants in genes associated with dominantly-inherited Mendelian disorders and calculate the incidence for selected recessive disorders, demonstrating the clinical usefulness of the present study. Finally, we observe that whole-genome and HLA imputation could be significantly improved compared to available datasets since rare variation represents the largest proportion of input from WGS. These results demonstrate that even smaller sample sizes of underrepresented populations bring relevant data for genomic studies, especially when exploring analyses allowed only by WGS.

Whole genome sequencing (WGS) data on non-European and admixed individuals remains scarce. Here, the authors analyse WGS data from 1,171 admixed elderly Brazilians from a census cohort, characterising population-specific genetic variation and exploring the clinical utility of this expanded dataset.

Comparison of Anaerobic Exercise Capacity in Children With Familial Mediterranean Fever and Healthy Controls

BACKGROUND/OBJECTIVE

Anaerobic exercise capacity is an important component of performing daily activities during childhood. However, diminished anaerobic exercise capacity has been reported in children with chronic conditions. Therefore, the aim of this study was to compare anaerobic exercise capacities between children with familial Mediterranean fever (FMF) and healthy peers.

METHODS

Twenty-one children with FMF (FMF group) and 21 physically matched healthy controls (control group) were included. Peak power, peak power/kg, average power, and average power were evaluated using the Wingate Anaerobic Test.

RESULTS

The peak power (FMF group: 254.8 W [IQR 25/75: 216.4/293.0 W] vs control group: 333.7 W [IQR 25/75: 241.3/570.5 W], p = 0.009), peak power/kg (FMF group: 6.3 W/kg [IQR 25/75: 5.2/7.0 W/kg] vs control group: 7.0 W/kg [IQR 25/75: 6.1/8.6 W/kg], p = 0.046), average power (FMF group: 186.0 W [IQR 25/75: 164.3/211.2 W] vs control group: 231.8 W [IQR 25/75: 181.8/338.1 W], p = 0.006), and average power/kg (FMF group: 4.5 W/kg [IQR 25/75: 3.8/5.0 W/kg] vs control group: 5.1 W/kg [IQR 25/75: 4.2/5.9 W/kg], p = 0.040) were found significantly higher in the control group compared with FMF group.

CONCLUSIONS

Children with FMF seems to have diminished anaerobic exercise capacity compared with their healthy peers.

Atypical Familial Mediterranean Fever in a Japanese Boy with Heterozygous MEFV p.Ser503Cys Exon 5 Variant

Periodic fever syndromes are heterogeneous diseases. Familial Mediterranean fever (FMF) is one of the hereditary periodic fever diseases caused by a Mediterranean fever (MEFV) gene abnormality. FMF can be categorized as typical or atypical, based on clinical findings and genetic screening. Atypical FMF has a wide variation of clinical findings and disease-causing mutations of MEFV. Therefore, it is sometimes difficult to diagnose an unknown fever as FMF. To date, a large number of various typical and atypical FMF cases have been reported in Japan. Here, we describe a Japanese boy with heterozygous MEFV p.Ser503Cys exon 5 variant who developed periodic fever. He was treated with colchicine; a complete eradication of his fever and various accompanying symptoms have been subsequently achieved for more than a year. Given that there have been a few reports about patients with this variant, little is known about the genetic and phenotypic role of heterozygous MEFV p.Ser503Cys exon 5 variant. It is therefore imperative to consider atypical FMF as a differential diagnosis when a periodic fever is encountered. Furthermore, we suggest that it is worthwhile to integrate MEFV gene analysis with the potential effects of colchicine treatment in patients with periodic fever.

miRNAs as attractive diagnostic and therapeutic targets for Familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is a hereditary early-onset disease that causes periodical fever attack, excessive release of IL-1β, serositis, arthritis and peritonitis. Genetic analyses conducted on FMF patients (mutated and non-mutated) have highlighted that additional contributing factors such as epigenetics and environment play a role in clinical manifestations of FMF. Recently researchers report that microRNAs (miRNAs), implicated in epigenetic mechanisms, may contribute to the pathogenesis of FMF. miRNAs, a member of the captivating noncoding RNA family, are the single-strand transcripts that work in physiological and pathophysiological processes by regulating target gene expression. Recent studies have shown that miRNAs are associated with various mechanisms involved in the pathogenesis of FMF, such as apoptosis, inflammation and autophagy. Moreover, these miRNAs molecules might have potential use in treatment, therapeutic response monitoring and the diagnosis of subtypes of the disease in the future. Motivated by these potential benefits (diagnostic and therapeutic) of miRNAs, we focus on recent advances of clinical significances and potential action mechanisms of miRNAs in FMF pathogenesis and discuss their potential use for FMF.

Familial Mediterranean Fever and COVID-19: Friends or Foes?

Familial Mediterranean Fever (FMF) and COVID-19 show a remarkable overlap of clinical symptoms and similar laboratory findings. Both are characterized by fever, abdominal/chest pain, elevation of C-reactive protein, and leukocytosis. In addition, colchicine and IL-1 inhibitors treatments that are effective in controlling inflammation in FMF patients have recently been proposed for off-label use in COVID-19 patients. Thus, FMF may resemble a milder recapitulation of the cytokine storm that is a hallmark of COVID-19 patients progressing to severe disease. We analyzed the sequence of the MEFV-encoded Pyrin protein - whose mutations cause FMF- in mammals, bats and pangolin. Intriguingly, although Pyrin is extremely conserved in species that are considered either a reservoir or intermediate hosts for SARS-CoV-2, some of the most common FMF-causing variants in humans are present as wildtype residues in these species. We propose that in humans, Pyrin may have evolved to fight highly pathogenic infections.

Vitamin D binding protein genotype frequency in familial Mediterranean fever patients

Objective: Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent short episodes (1-3 days) of inflammation and fever. FMF is associated with MEFV gene mutations but some patients with FMF symptoms do not have a mutation in the coding region of the MEFV gene. Vitamin D binding protein (VDBP) has important functions, including transporting vitamin D and its metabolites to target cells. Circulating levels of vitamin D are decreased in several inflammatory conditions, including FMF. Thus, we hypothesize that VDBP may play a crucial role in FMF pathogenesis, in addition to the MEFV gene. Method: VDBP genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism in 107 FMF patients and 25 healthy individuals without FMF or family history. For this, after amplification of genomic DNA, PCR products were digested with restriction enzymes HaeIII and StyI and evaluated electrophoretically. Results: We observed a statistically significant difference in the frequency of the 1F-2 genotype. The frequency of allele 2 was significantly higher and allele 1S was significantly lower compared to the [MEFV(-)] group and healthy controls (p = 0.034, 0.001, and 0.012, respectively). We observed a significant association between the presence of allele 2 and amyloidosis (p = 0.026) and arthritis (p = 0.044) in the [MEFV(-)] group. Conclusion: Our results suggest that FMF symptoms in the absence of MEFV gene mutations may be due to the presence of VDBP allele 2. Therefore, VDBP genotype may explain the symptoms in FMF [MEFV(-)] patients.

Familial Mediterranean Fever: Assessing the Overall Clinical Impact and Formulating Treatment Plans

Recurrent self-limited attacks of fever and short-lived inflammation in the serosal membranes, joints, and skin are the leading features of familial Mediterranean fever (FMF), the most common autoinflammatory disorder in the world, transmitted as autosomal recessive trait caused by MEFV gene mutations. Their consequence is an abnormal function of pyrin, a natural repressor of inflammation, apoptosis, and release of cytokines. FMF-related mutant pyrins are hypophosphorylated following RhoA GTPases’ impaired activity and show a propensity to relapsing uncontrolled systemic inflammation with inappropriate response to inflammatory stimuli and leukocyte spread to serosal membranes, joints or skin. Typical FMF phenotype 1 consists of brief episodes of inflammation and serositis, synovitis, and/or erysipelas-like eruption, whereas phenotype 2 is defined by reactive amyloid-associated (AA) amyloidosis, which is the most ominous complication of FMF, in otherwise asymptomatic individuals.

Furthermore, FMF phenotype 3 is referred to the presence of two MEFV mutations with neither clinical signs of FMF nor AA amyloidosis. The influence of epigenetic and/or environmental factors can contribute to the variable penetrance and phenotypic heterogeneity of FMF. Colchicine, a tricyclic alkaloid with anti-microtubule and anti-inflammatory properties, is the bedrock of FMF management: daily administration of colchicine prevents the recurrence of FMF attacks and the development of secondary AA amyloidosis. Many recent studies have also shown that anti-interleukin-1 treatment is the best therapeutic option for FMF patients nonresponsive or intolerant to colchicine. This review aims to catch readers’ attention to the clinical diversity of phenotypes, differential diagnosis, and management of patients with FMF.

Familial Mediterranean fever: breaking all the (genetic) rules

OBJECTIVE

FMF is an inherited autoinflammatory syndrome, characterized by attacks of painful periodic fever caused by diffuse serositis and risk of secondary amyloidosis due to IL-1β-mediated inflammation. The disease appears to be transmitted through autosomal recessive mutations in the MEFV gene encoding the pyrin protein Although more than 300 variants have been reported worldwide so far, their association with symptom severity, the relative frequencies in different populations and the disease penetrance are far from being completely understood. We investigated genotype-phenotype correlations in two large nuclear families and verified whether commonly used web-based tools can usefully predict variant pathogenicity in FMF.

METHODS

Peripheral blood samples were obtained from 15 patients of two families who had been diagnosed with FMF according to international criteria. The entire MEFV coding region was sequenced in all subjects, and 179 MEFV variants were surveyed with five different pathogenicity predictors.

RESULTS

The inheritance of FMF could not be explained by traditional autosomal recessivity in both families. In silico tools demonstrated a significant association of variants' pathogenicity with their position along the coding sequence but not with variants' frequency.

CONCLUSION

By describing two large families with paradigmatic complexity of FMF genetics, we conclude that established concepts in assessing the causative role of variants identified in mutation screening cannot be easily translated into appropriate genetic counselling in FMF. Furthermore, we demonstrate that variants frequently associated with severe disease are not predicted to significantly impact protein function using in silico algorithms.

Familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is the oldest and the most frequent of all described hereditary periodic fever syndromes. The populations originating from Mediterranean basin carry the highest risk for FMF however it is being increasingly recognized in many parts of the world. It is an autoinflammatory disease with an autosomal recessive transmission. In the majority of the patients it is related with mutations in the MEFV gene that encodes a protein named pyrin. This protein has been shown to act as a regulator of inflammation mediated by IL-1β, which plays a major role in the pathogenesis of FMF. Approximately one-third of the patients have either a single or no mutation which raise questions about its mode of inheritance. FMF is a clinical diagnosis and characterized by self-limited bouts of fever and serositis. The main long-term complication of the disease is AA amyloidosis. The mainstay of treatment is life-long colchicine given daily to prevent the recurrence of febrile attacks and the development of amyloidosis. Patients with insufficient response to colchicine may be treated with anti IL-1 agents.

Familial Mediterranean fever in Jordanian Children: single centre experience

Background

Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder caused by mutations in the Mediterranean Fever (MEFV) gene. The disease is especially common among Mediterranean ancestry, mostly Armenian, Turkish, Jewish and Arab populations. Our aim is to describe clinical phenotype, and genotype of FMF in the Jordanian children.

Patients and Methods

A retrospective analysis was conducted on paediatric patients who were below 14 years of age and diagnosed as FMF at Queen Rania Children's Hospital in Jordan between 2014 and 2017.

Results

A total of 196 paediatric patients diagnosed with FMF were included; 54% females and 46% males. The mean age of patients at time of study was 7.8 years, at disease onset was 4.9 years, and at time of diagnosis was 6.6 years. The most common presenting features were abdominal pain (91.8%), fever (73%), arthralgia (16.8 %), and myalgia (12.8%). MEFV gene mutations were homozygous in 47 (24%) patients, heterozygous in 87 (44.4%) patients, compound heterozygous in 55 (28.1%), and negative genotype in 7 (3.6%) patients. Five mutations were the most frequent; M694V, V726A, E148Q, M680I, M694I. All patients were colchicine responsive. We reported only one case of amyloidosis.

Conclusion

The five FMF founder mutations: M694V, V726A, E148Q, M680I, and M694I were the most common in Jordanian children, but had a different order from other ethnic groups.

Five Cases of Familial Mediterranean Fever in Japan: The Relationship with MEFV Mutations

Familial Mediterranean fever (FMF) is the most common genetic autoinflammatory disease, but it has been considered a rare disease in Japan. We herein describe five patients with FMF who were diagnosed both clinically and genetically at a single Japanese institute. A genetic investigation of Mediterranean fever (MEFV) detected heterozygosity for the compound mutations L110P/E148Q (n=2) and L110P/148Q/P369S/R406Q (n=1), and heterozygosity for M694I (n=1) and S503C (n=1). Colchicine prevented febrile attacks and accompanying symptoms in four patients. One patient with an S503C mutation showed resistance. Physicians should be aware of the characteristic symptoms, as well as the more unusual symptoms such as headache, when diagnosing FMF.

CBL mutation and MEFV single-nucleotide variant are important genetic predictors of tumor reduction in glucocorticoid-treated patients with chronic myelomonocytic leukemia

Glucocorticoid (GC) therapy occasionally relieves tumor-related fever and promotes tumor reduction in patients with chronic myelomonocytic leukemia (CMML). A mutation analysis of 24 patients with CMML revealed the relationship of GC effectiveness, defined as a monocyte reduction of > 50% within 3 days of methylprednisolone administration, with the MEFV single-nucleotide variant (SNV) and CBL mutation. Lipopolysaccharide-stimulated monocytes harboring MEFV E148Q produced greater amounts of IL-1β and TNF-α than did wild-type monocytes; this was effectively suppressed by GC. Primary CMML cells harboring the MEFV SNV and CBL mutation, and the myelomonocytic leukemia cell line GDM-1, harboring the CBL mutation, were both more significantly suppressed than non-mutated cells following GC treatment in the presence of GM-CSF. A loss-of-function CBL mutation prolonged STAT5 phosphorylation after GM-CSF stimulation, which was rapidly terminated in both patient samples and GDM-1 cells. In conclusion, GC therapy effectively treats CMML cells harboring the MEFV SNV and CBL mutation by reducing inflammatory cytokine production and terminating prolonged STAT5 phosphorylation in the GM-CSF signaling pathway.

Genetic epidemiology of familial Mediterranean fever through integrative analysis of whole genome and exome sequences from Middle East and North Africa

Familial Mediterranean fever (FMF), an autosomal recessive and rare autoinflammatory disease is caused by genetic mutations in the MEFV gene and is highly prevalent in the Mediterranean basin. Although the carrier frequency of specific disease variants in the MEFV gene has been reported from isolated studies, a comprehensive view of variants in the Mediterranean region has not been possible due to paucity of data. The recent availability of whole-genome and whole-exome datasets prompted us to study the genetic epidemiology of MEFV variants in the region. We assembled data from 5 datasets encompassing whole-genome and whole-exome datasets for 2115 individuals from multiple subpopulations in the region and also created a compendium for MEFV genetic variants, which were further systematically annotated as per the American College of Medical Genetics and Genomics (ACMG) guidelines. Our analysis points to significant differences in allele frequencies in the subpopulations, and the carrier frequency for MEFV genetic variants in the population to be about 8%. The MEFV gene appears to be under natural selection from our analysis. To the best of our knowledge, this is the most comprehensive study and analysis of population epidemiology of MEFV gene variants in the Middle East and North African 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.

Coupling clinical exome sequencing with functional characterization studies to diagnose a patient with familial Mediterranean fever and MED13L haploinsufficiency syndromes

Clinicians should consider that clinical exome sequencing provides the unique potential to disentangle complex phenotypes into multiple genetic etiologies. Further, functional studies on variants of uncertain significance are necessary to arrive at an accurate diagnosis for the patient.

Global Carrier Rates of Rare Inherited Disorders Using Population Exome Sequences

Exome sequencing has revealed the causative mutations behind numerous rare, inherited disorders, but it is challenging to find reliable epidemiological values for rare disorders. Here, I provide a genetic epidemiology method to identify the causative mutations behind rare, inherited disorders using two population exome sequences (1000 Genomes and NHLBI). I created global maps of carrier rate distribution for 18 recessive disorders in 16 diverse ethnic populations. Out of a total of 161 mutations associated with 18 recessive disorders, I detected 24 mutations in either or both exome studies. The genetic mapping revealed strong international spatial heterogeneities in the carrier patterns of the inherited disorders. I next validated this methodology by statistically evaluating the carrier rate of one well-understood disorder, sickle cell anemia (SCA). The population exome-based epidemiology of SCA [African (allele frequency (AF) = 0.0454, N = 2447), Asian (AF = 0, N = 286), European (AF = 0.000214, N = 4677), and Hispanic (AF = 0.0111, N = 362)] was not significantly different from that obtained from a clinical prevalence survey. A pair-wise proportion test revealed no significant differences between the two exome projects in terms of AF (46/48 cases; P > 0.05). I conclude that population exome-based carrier rates can form the foundation for a prospectively maintained database of use to clinical geneticists. Similar modeling methods can be applied to many inherited disorders.

A case of a ten-year old girl with dominantly inherited Familial Mediterranean fever in Republic of Macedonia

The Familial Mediterranean fever (FMF, MIM249100) is an autoimflammatory genetic disease characterized with recurrent painful attacks in the abdomen, chest or joints, usually accompanied with high body temperature. It is classically inherited in an autosomal recessive manner. It is associated with mutations of the MEFV gene, coding for the protein pyrin. More than 140 mutations of the MEFV gene are defined worldwide. Despite the progress in establishing reliable tests practical for routine use, as much as 20% of the patients with FMF remain without a detectable mutation in the MEFV gene. This is the main reason why the diagnosis of FMF remains still a clinical one, according to Tel Hashomer criteria. A 10-year old girl admitted to the Clinic of Pediatrics at the Faculty of Medicine in Skopje for unexplained fever. After numerous laboratory analyses and specialist consultations were done, genetic testing for FMF was requested. The presence of an heterozygous mutation E148Q was confirmed at the Institute for Immunobiology and Human Genetics using a PCR based, reverse hybridization method. Administration of colchicine, the therapy of choice, in a dose of 1.5 mg/day, lead to complete resolution of the symptoms within some days following commencement. Although the disease is classically inherited in a recessive manner, some atypical cases of autosomal dominant inheritance are described. Our patient may be another example supporting the unusual dominant inheritance, since the heterozygous state for the E148Q mutation was the only positive finding in the genotyping of the 12 most frequent MEFV mutations.