Comparison of amplification refractory mutation system and polymerase chain reaction-restriction fragment length polymorphism techniques used for the investigation of MEFV gene exon 10 point mutations in familial Mediterranean fever patients living in Cukurova region (Turkey)

Familial Mediterranean fever (FMF) is an autosomal recessive inherited disease characterized by recurrent fever, serositis and arthritis. The disease is highly prevalent in Mediterranean basin populations. Recently, the gene responsible for FMF (MEFV) was cloned and at least 40 MEFV gene mutations have been identified. The most frequently observed mutations in the MEFV gene are M694V, M694I, M680I, and V726A. These occur within exon 10 of the gene, and account for 85% of the known MEFV alleles. In this study, the reliability and economical aspects of amplification refractory mutation system (ARMS) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were compared for analyzing the frequencies of the major point mutations of 90 unrelated patients with FMF from the Cukurova region in Turkey. Both techniques yielded similar results: The ratio of independent alleles of 90 patients carrying one of the tested mutations was 81.1%; patients consisted of 12 different genotypes. In 64 of 90 patients (71.1%) mutations were observed in both alleles. Thirty-six patients (40%) were homozygous for the same mutation, 28 (31.1%) were heterozygous for different mutations. Eighteen patients (20%) were heterozygous for one allele with one of the four mutations but the other allele was unknown. In 8 patients (8.8%) no mutation could be detected. The most frequently observed mutation was M694V (51.66%), followed by M680I (17.22%), V726A (10.55%), and M694I (1.66%). In conclusion ARMS and PCR-RFLP techniques were equally reliable to detect the mutations in Turkish FMF patients. However, the ARMS technique was found to be more rapid and economical than the PCR-RFLP techniques.     

Clinical and molecular analysis of common MEFV gene mutations in familial Mediterranean fever in Sivas population

Familial Mediterranean fever (FMF) is the most frequent hereditary inflammatory disease characterized by self-limited recurrent attacks of fever and serositis. The aim of the current study is to determine the frequency of the mutations in 365 suspected FMF patients and to reveal whether there is a correlation between genotype and phenotype of these patients. All patients were clinically examined according to Tell-Hashomer FMF criteria and were screened genetically in terms of common 12 Mediterranean fever gene (MEFV) mutations. Various point mutations were detected in 270 (74%) patients. The most frequent mutation was M694V (26.85% of the alleles) and was followed by E148Q (15.55%), M680I (G/C) (9.62%) and V726A (7.96%). Patients who bear M694V homozygous mutation had most severe disease phenotype and high risk for amyloidosis (P = 0.04). Our results indicate that Sivas population has a wide range of heterozygous mutated carriers of MEFV gene and there is a high frequency of E148Q allele when compared to the other Mediterranean groups.     

<Emphasis Type="Italic">MEFV</Emphasis> gene mutations spectrum among Lebanese patients referred for Familial Mediterranean Fever work-up: Experience of a major tertiary care center

Familial Mediterranean Fever (FMF) is an autosomal recessive inflammatory disorder predominantly affecting people living in or originating from areas around the Mediterranean Sea, mainly Jews, Armenians, Turks, and Arabs. It is characterized by recurrent attacks of inflammation of serosal membranes and fever resulting in acute abdominal, chest, or joint pain. Over 50 MEditerranean FeVer (MEFV) mutations and polymorphisms have been identified in FMF patients. The objective of this study was to analyze the distribution and frequencies of 12 MEFV mutations in 266 referred Lebanese patients using a reverse-hybridization assay. Of the 266 patients, 129 (48.5%) were positive for at least one mutation and 137 (51.5%) had no mutations detected. Of the 129 patients with mutations, 35 were homozygous, 41 were compound heterozygous and 53 were heterozygous. The five most common mutations M694V, E148Q, V726A, M694I and M680I (G/C) accounted for 26.1, 22.2, 21.3, 9.6 and 7.7%, respectively. The A744S, F479L, R761H and I692del were encountered in 2.9% of patients; P369S and M680I (G/A) were found in 1.2% of patients while K695R was absent. The spectrum of the MEFV mutations among our sampled Lebanese FMF patients shows the high heterogeneity at the allelic level when compared to Arab and non-Arab populations. The most important feature was the relatively high frequency of the E148Q in our study group that allows us to question it as a mutation rather than a polymorphism. Further studies should be conducted to evaluate the role of the E148Q allele.     

Prevalence of known mutations in the MEFV gene in a population screening with high rate of carriers

The Familial Mediterranean Fever (FMF) shows an autosomal recessive pattern of inheritance and affects certain ethnic groups. Disease is caused by mutations in MEFV gene and more than 180 mutations have been defined in affected individuals. Current study aimed to determine the frequency-type of the mutations for MEFV gene in Sivas??middle Anatolian city. The cohort was composed of 3340 patients. MEFV gene mutations were studied by multiplex PCR based reverse hybridization stripAssay method. Patients?? clinical features were; family history: 68%, erysipelas-like erythema: 17.6%, fever: 89.9%, abdominal pain: 84.2%, peritonitis: 90.2%, arthritis: 33%, pleuritis: 14.2%, parental consanguinity: 21.2%. Current results revealed that M694V is the most frequent mutation (43.12%), followed by E148Q (20.18), M680I(G/C) (15.00%) and V726A (11.32%). The study population has a high rate of carriers and the E148Q mutation frequency was found to be highest when compared to the other regions of Turkey and other Mediterranean groups.     

Phenotype-genotype updates from familial Mediterranean fever database registry of Mansoura University Children’ Hospital,Mansoura, Egypt

BACKGROUND:

Familial Mediterranean fever (FMF) is autosomal recessive disease that affects people from Mediterranean region, Europe and Japan. Its gene (Mediterranean fever [MEFV]) has more than 100 mostly non-sense mutations.

OBJECTIVES:

The objective of the following study is to provide some phenotype-genotype correlates in FMF by categorizing the Egyptian FMF cases from Delta governorates after analysis of the four most common mutations of MEFV gene (M680I, M694I, M694V, V726A).

SUBJECTS AND METHODS:

Clinically, suspected FMF cases using Tel-Hashomer criteria were enrolled in the study. Cases were referred to Mansoura University Children''s Hospital that serves most of the most middle Delta governorates, in the period from 2006 to 2011. Subjects included 282 males and 144 females, mean age of onset 9.3 ± 2.2 years. All cases were analyzed for these mutations using amplification refractory mutation system based on the polymerase chain reaction technique. Five FMF patients agreed to undergo renal biopsy to check for development of amyloidosis. Analysis of data was carried out using SPSS (SPSS, Inc., Chicago, IL, USA).

RESULTS:

Mutation was found in 521 out of 852 studies alleles, the most frequent is M694V (35.4%) followed by M694I, V726A and M680I. 11 cases were homozygous; 7 M694V, 3 M680I and only one M694I case. Severe abdominal pain occurred in 31 (7.28%) but severe arthritis in 103 cases (24.2%). Strong association was found between arthritis and homozygous mutant compared with single and double heterozygous (72.7% vs. 33.3% and 20.24%, P < 0.001). Four amyloid cases were M694V positive.

CONCLUSION:

M694V allele is the most common among Egyptian FMF especially those with amyloidosis. We recommend routine check for amyloidosis in FMF cases to statistically validate this link.     

Common Familial Mediterranean Fever gene mutations in a Turkish cohort

Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disorder with the responsible gene of MEFV which primarily affects Jewish, Armenian, Turkish and Arab populations. The FMF gene (MEFV) has recently been cloned to chromosome 16p, which encodes pyrin. In the present study, we enrolled 2,067 unrelated patients with the suspicion of FMF in Middle Anatolia between the years 2006–2009 and identified the 12 MEFV mutations. DNA was amplified by PCR and subjected to reverse hybridization for the detection of MEFV gene mutations. Among the 2,067 patients, 866 (41.9%) were males and 1,201 (58.1%) were females. The mutations were homozygous in 176 (16.85%) patients, compound heterozygous in 314 (30.1%) patients, heterozygous in 546 (52.25%) patients and the other forms of mutations were found in 8 patients (0.76%). No mutation was detected in 1,023 (49.5%) patients. The most frequent mutations were M694V, M680I (G/C), E148Q and V726A. We could not find any significant differences between the two common mutations according to the gender. The high incidence of MEFV gene mutations in the Turkish population indicated that newborn screening may be discussed in the future. Because of the ethnic origin of Anatolia, larger serial analyses are necessary to investigate the rate and coexistence of these mutations.     

Screening of common and novel familial mediterranean fever mutations in south-east part of Turkey

Familial mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder (MIM# 249100), particularly common in populations of Mediterranean extraction. MEFV gene, responsible for FMF, encoding pyrin has recently been mapped to chromosome 16p13.3. In the present study, 3,341 unrelated patients with the suspicion of FMF in south-east part of Turkey between the years 2009 and 2013 were enrolled and genomic sequences of exon 2 and exon 10 of the MEFV gene were scanned for mutations by direct sequencing. We identified 43 different type of mutations and 9 of them were novel. DNA was amplified by PCR and subjected to direct sequencing for the detection of MEFV gene mutations. Among the 3,341 patients, 1,598 (47.8 %) were males and 1,743 (52.1 %) were females. The mutations were heterozygous in 806 (62.3 %), compound heterozygous in 188 (14.5 %), homozygous in 281 (21.8 %) and mutations had complex genotype in 17 (1.32 %) patients. No mutation was detected in 2,051 (61.4 %) patients. The most frequent mutations were M694V, E148Q, M680I(G/C) and V726A. We could not find any significant differences between the two common mutations according to the gender. Molecular diagnosis of MEFV is a useful tool in clinical practice, thus a future study relating to genotype/phenotype correlation of FMF in more and larger group in Turkish population involving the whole MEFV gene mutations is necessary.     

Familial Mediterranean fever in Syrian patients: <Emphasis Type="Italic">MEFV</Emphasis> gene mutations and genotype–phenotype correlation

Familial Mediterranean fever is an autosomal recessive disorder characterized by recurrent attacks of abdominal pain, synovitis and pleuritis. MEFV gene mutations are responsible for the disease. The objective of this study was to identify the frequency and distribution of 12 MEFV mutations in 153 Syrian patients and perform a genotype–phenotype correlation in the patients’ cohort. Of the 153 unrelated patients investigated, 97 (63.4%) had at least one mutation. The most frequent mutation was M694V (36.5%), followed by V726A (15.2%), E148Q (14.5%), M680I (G/C) (13.2%), and M694I (10.2%) mutations. Rare mutations (R761H, A744S, M680I (G/A), K695R, P369S, F479L and I692del) were also detected in the patients. M694V was associated with the severe form of the disease. The identification of a significant number of FMF patients with no mutations or only one known mutation identified indicates the presence of new mutations in the MEFV gene which will be investigated in the future.     

Frequency of MEFV gene mutations in Hatay province,Mediterranean region of Turkey and report of a novel missense mutation (I247V)

In the present study, 1000 patients with clinical suspicion of FMF were retrospectively reviewed to determine the spectrum of MEFV gene mutations by using DNA sequence analysis between September, 2008 and April, 2012. Sixteen different mutations and 55 different genotypes were detected in 618 of 1000 patients. Among 16 different mutations, R202Q (21.35%) was the most frequently observed mutation; followed by E148Q (8.85%), M694V (7.95%), M680I (2.40%), V726A (1.85%), M694I (0.95%), A744S (0.80%), R761H (0.55%), P283L (0.35%), K695R (0.20%), E230K (0.15%), L110P (0.10%), I247V (0.05%), G196W (0.05%) and G304R (0.05%). In the present study, a novel missense mutation (I247V) and a silent variant (G150G) were identified in the MEFV gene. On the other hand, P238L, G632A and G304R mutations are the first cases reported from Turkey. Our results indicated that MEFV mutations are highly heterogeneous in our study population as in other regions of Turkey and mutation screening techniques such as PCR-RFLP, amplification refractory mutation system or reverse hybridization do not adequately detect uncommon or novel mutations. Therefore, it was proven that sequence analysis of the MEFV gene could be useful for detection of rare or unknown mutations.     

Two novel mutations R653H and E230K in the Mediterranean fever gene associated with disease

Familial Mediterranean fever (FMF) is an autosomal recessive disorder caused by mutations in the Mediterranean fever gene (MEFV). We describe two novel missense mutations in MEFV, R653H and E230K. Both were found in compound heterozygosity with the mutation M694V in single Turkish patients with clinical syndromes characteristic for FMF. DNA sequencing and PCR-RFLP typing of the families confirmed the mutations and verified recessive modes of inheritance.     

Comparison of the results of PCR-RFLP and reverse hybridization methods used in molecular diagnosis of FMF

Familial Mediterranean fever (FMF) is characterized by recurrent fever, serositis, and arthritis. Due to the abundance of mutations and clinical heterogeneity of the disease, different screening methods have been developed. In this study, we aimed to compare our findings of mutations determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with reverse hybridization (RH) methods. In 152 of 263 patients (57.79%) different mutations were determined with RH. Allelic frequencies were E148Q 6.84%, M680I(G/C) 3.61%, M694V 20.91%, V726A 7.03%, P369S 1.33%, F479L 0.19%, M680I(G/A) 0.76%, M694I 0.57%, K695R 0.57%, A744S 0.38%, R731H 0.38%, and del1692 0%. Frequent mutations were also confirmed by PCR-RFLP. There were no conflicting results between the two methods. Four of these genotypes were homozygous for a single mutation, 15 were heterozygous for two mutations, 8 were heterozygous for a single mutation, 1 was heterozygous for three mutations, and 1 was homozygous for one mutation and heterozygous for another mutation. It has been reported that analytical sensitivity of RH is 97%. We did not find a discrepancy between the two methods. In 21 patients, we detected additional mutations with RH. This finding was regarded as an advantage of RH, and we concluded that this assay is a useful method for detection of first stage FMF mutation screening.     

Study of the mutation M694V of familial Mediterranean fever in Jews

Familial Mediterranean fever (FMF) is a recessively inherited disorder characterized by episodes of fever with abdominal pain, pleurisy, or arthritis. The familial Mediterranean fever gene, designated MEFV, was recently cloned, and the missense mutation M694V accounting for most of the patients with this disease was identified. The objective of the present study was to establish frequencies of the M694V mutation in three groups of Jews. The subjects studied were 381 Sephardi, 256 Ashkenazi, and 65 Oriental Jews, all male subjects, previously collected for an anthropological study, independent of their FMF status. The M694V mutation in the 702 samples was assessed by amplifying genomic DNA with the use of primers that selectively amplify the normal or altered DNA sequence of the M694V mutation, by the amplification refractory mutation system (ARMS). In our sample of Sephardi Jews, the frequency of the M694V mutation is elevated (10.9%), and this is also the case for Oriental Jews (9.2%). In our sample of Ashkenazis, the M694V allele frequency is very low (0.8%).     

Genotype-phenotype correlation in Japanese patients with familial Mediterranean fever: differences in genotype and clinical features between Japanese and Mediterranean populations

Introduction

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disease characterized by recurrent self-limiting fever and serositis that mainly affects Mediterranean populations. Many patients with FMF have been reported in Japan due to increasing recognition of this condition and the availability of genetic analysis for the gene responsible, MEFV. The present study was performed to elucidate the clinical characteristics of Japanese FMF patients and to examine the precise genotype-phenotype correlation in a large cohort of Japanese FMF patients.

Methods

We analyzed the MEFV genotypes and clinical manifestations in 116 patients clinically diagnosed as having FMF and with at least one mutation.

Results

The most frequent mutation in Japanese patients was E148Q (40.2%), followed by M694I (21.0%), L110P (18.8%), P369S (5.4%), and R408Q (5.4%). In contrast, common mutations seen in Mediterranean patients, such as M694V, V726A, and M680I, were not detected in this population. The clinical features with M694I were associated with more severe clinical course compared to those seen with E148Q. P369S/R408Q showed variable phenotypes with regard to both clinical manifestations and severity. Patients with M694I showed a very favorable response to colchicine therapy, while those with P369S and R408Q did not.

Conclusions

Clinical features and efficacy of treatment in Japanese FMF patients vary widely according to the specific MEFV gene mutation, and therefore genetic analysis should be performed for diagnosis in cases of Japanese FMF.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0439-7) contains supplementary material, which is available to authorized users.     

Defect of suppression of inflammasome-independent interleukin-8 secretion from SW982 synovial sarcoma cells by familial Mediterranean fever-derived pyrin mutations

Familial Mediterranean fever (FMF) is a recessive inherited autoinflammatory syndrome. Patients with FMF have symptoms such as recurrent fever and abdominal pain, sometimes accompanied by arthralgia. Biopsy specimens have revealed substantial neutrophil infiltration into synovia. FMF patients have a mutation in the Mediterranean fever gene, encoding pyrin, which is known to regulate the inflammasome, a platform for processing interleukin (IL)-1β. FMF patients heterozygous for E148Q mutation, heterozygous for M694I mutation, or combined heterozygous for E148Q and M694I mutations, which were found to be major mutations in an FMF study group in Japan, suffer from arthritis, the severity of which is likely to be lower than in FMF patients with M694V mutations. Expression plasmids of wild-type (WT) pyrin and mutated pyrin, such as E148Q, M694I, M694V, and E148Q+M694I, were constructed, and SW982 synovial sarcoma cells were transfected with these expression plasmids. IL-8 and IL-6 were spontaneously secreted from the culture supernatant of SW982 cells without any stimulation, whereas IL-1β and TNF-α could not be detected even when stimulated with lipopolysaccharide. Notably, two inflammasome components, ASC and caspase-1, could not be detected in SW982 cells by Western blotting. IL-8 but not IL-6 secretion from SW982 cells was largely suppressed by WT pyrin, but less suppressed by mutated pyrin, which appeared to become weaker in the order of E148Q, M694I, E148Q+M694I, and M694V mutations. As for IL-8 and IL-6, similar results were obtained using stable THP-1 cells expressing the WT pyrin or mutated pyrins, such as M694V or E148Q, when stimulated by LPS. In addition, IL-8 secretion from mononuclear cells of FMF patients was significantly higher than that of healthy volunteers when incubated on a culture plate. Thus, our results suggest that IL-8 secretion from SW982 synovial sarcoma cells suppressed by pyrin independently of inflammasome is affected by pyrin mutations, which may reflect the activity in FMF arthritis.     

The spectrum of FMF mutations and genotypes in the referrals to molecular genetic laboratory at Kırıkkale University in Turkey

Familial Mediterranean Fever (FMF) is an autosomal recessive genetic disorder characterised by recurrent and self-limited abdominal pain, synovitis and pleuritis. MEFV gene mutations are responsible from the disease and its protein product, pyrin or marenostrin, plays an essential role in the regulation of the inflammatory reactions. MEFV gene contains 10 exons and most of the mutations have been found on the last exon. Up to date, 152 mutations and polymorpisms have been reported inwhere V726A, M694V, M694I, M680I and E148Q are the most common mutations. In this study, MEFV allele frequencies of 136 individuals (60 from Pediatry, 76 from Internal Medicine) have been evaluated, and compared with each other. Asymptomatic individuals with FMF family history (4 from Pediatry, 6 from Internal Medicine) were excluded from the analysis. The prominent mutations indicated in the Pediatry group are V726A, M694V and M680I (G/C) and with the allele frequency of 0.06, 0.05 and 0.04 respectively while they were E148Q, M694V, M680I (G/C) in the Internal Medicine group with the allele frequency of 0.12, 0.08 and 0.04. The E148Q mutation is significantly overrepresented in the adult referrals (P = 0.02). Mutation on both alleles was observed in only 12% of cases. Overall mutation frequency was low, seen in 26.2% (66/252). However, when only diagnosed patients were analyzed it is 72.7% (16/22). It is also interesting that 63% of individuals are female that there may be sex influence on FMF phenotype.     

Mutation and haplotype studies of familial Mediterranean fever reveal new ancestral relationships and evidence for a high carrier frequency with reduced penetrance in the Ashkenazi Jewish population

Familial Mediterranean fever (FMF) is a recessive disorder characterized by episodes of fever with serositis or synovitis. The FMF gene (MEFV) was cloned recently, and four missense mutations were identified. Here we present data from non-Ashkenazi Jewish and Arab patients in whom we had not originally found mutations and from a new, more ethnically diverse panel. Among 90 symptomatic mutation-positive individuals, 11 mutations accounted for 79% of carrier chromosomes. Of the two mutations that are novel, one alters the same residue (680) as a previously known mutation, and the other (P369S) is located in exon 3. Consistent with another recent report, the E148Q mutation was observed in patients of several ethnicities and on multiple microsatellite haplotypes, but haplotype data indicate an ancestral relationships between non-Jewish Italian and Ashkenazi Jewish patients with FMF and other affected populations. Among approximately 200 anonymous Ashkenazi Jewish DNA samples, the MEFV carrier frequency was 21%, with E148Q the most common mutation. Several lines of evidence indicate reduced penetrance among Ashkenazi Jews, especially for E148Q, P369S, and K695R. Nevertheless, E148Q helps account for recessive inheritance in an Ashkenazi family previously reported as an unusual case of dominantly inherited FMF. The presence of three frequent MEFV mutations in multiple Mediterranean populations strongly suggests a heterozygote advantage in this geographic region.     

Mediterranean fever gene mutations: correlation with cytotoxic T‐lymphocyte‐associated antigen 4 gene polymorphism

Mutations in the Mediterranean fever (MEFV) gene lead to familial Mediterranean fever (FMF), a pro‐inflammatory state characterized by outbursts of inflammatory cytokines. The aims of this study were to identify the common mutations of MEFV gene in Egyptian patients with FMF, to study cytotoxic T lymphocyte associated antigen 4 (CTLA‐4) gene polymorphism and to evaluate correlations between CTLA4–1661 polymorphisms and MEFV mutations and clinical symptoms. Four hundred and twenty‐four patients with clinical pictures suspicious of FMF were enrolled in this study. Mutations in MEFV gene were confirmed by reversed hybridization. Patients with homozygous and compound heterozygous mutations and 120 healthy controls were investigated for polymorphism of ?1661 CTLA4 gene and the findings correlated with disease incidence and clinical symptoms of the disease. Ninety‐seven patients had single heterozygous mutations and 78 had compound heterozygous or homozygous MEFV gene mutations. M694I/V726A was the most common genotype (14.1%), followed by homozygous M694I. There was no statistically significant difference between patients and controls in incidence of ?1661 A/G single nucleotide polymorphism CTLA4 (P = 0.189), nor any significant correlation with any of the clinical symptoms of FMF and MEFV gene mutations.

     

<Emphasis Type="Italic">MEFV</Emphasis> mutations in patients with familial Mediterranean fever from the Aegean region of Turkey

Familial Mediterranean Fever (FMF) which is frequently present in Mediterranean populations is caused by mutations in the MEFV gene. According to recent data, MEFV mutations are not the only cause of FMF, but these are major genetic determinants which cause FMF. It has also been suggested that there may be a number of other genes causing FMF. The MEFV gene is located at 16p13.3 and encodes a protein, pyrin/marenostrin. More than 70 disease associated mutations and totally 186 mutations and polymorphisms have been defined in affected individuals. We have retrospectively evaluated the molecular test results of 1,201 patients identified as having FMF clinical symptoms referred to the Molecular Genetics Laboratory of the Department of Medical Genetics, Faculty of Medicine, Ege University, Izmir/Turkey over the last 4 years. Patients were tested for 12 common mutations in the MEFV gene using a strip assay method (Innogenetics, Belgium). Out of the 1,201 patients tested (2,402 chromosomes) in the Aegean region in Turkey, 654 (54.45%) did not carry any mutations, among the 547 (45.55%) patients with mutations 246 patients were either homozygous (101) or compound heterozygous (145), 296 carried only one detected mutation, and five patients had three mutations. Allelic frequencies for the four most common mutations in the mutation positive groups were 47.60% (M694V), 16.75% (E148Q), 12.95% (V726A), 11.94% (M680I G/C).The remaining alleles (10.76%) showed rare mutations which were R761H, P369S, A744S, K695R, F479L, M694I. When the frequencies of mutations detected in our group were compared to the frequencies reported in the other regions of Turkey, an increase in V726A mutation frequency was observed. No patient showed a I692del mutation which is sometimes evident in other Mediterranean populations.     

Identification of MEFV-independent modifying genetic factors for familial Mediterranean fever

Familial Mediterranean fever (FMF) is a recessively inherited disorder predisposing to renal amyloidosis and associated with mutations in MEFV, a gene encoding a protein of unknown function. Differences in clinical expression have been attributed to MEFV-allelic heterogeneity, with the M694V/M694V genotype associated with a high prevalence of renal amyloidosis. However, the variable risk for patients with identical MEFV mutations to develop this severe complication, prevented by lifelong administration of colchicine, strongly suggests a role for other genetic and/or environmental factors. To overcome the well-known difficulties in the identification of modifying genetic factors, we investigated a relatively homogeneous population sample consisting of 137 Armenian patients with FMF from 127 independent families living in Armenia. We selected the SAA1, SAA2, and APOE genes-encoding serum amyloid proteins and apolipoprotein E, respectively-as well as the patients' sex, as candidate modifiers for renal amyloidosis. A stepwise logistic-regression analysis showed that the SAA1alpha/alpha genotype was associated with a sevenfold increased risk for renal amyloidosis, compared with other SAA1 genotypes (odds ratio [OR] 6. 9; 95% confidence interval [CI] 2.5-19.0). This association, which was present whatever the MEFV genotype, was extremely marked in patients homozygous for M694V (11/11). The risk for male patients of developing renal amyloidosis was fourfold higher than that for female patients (OR=4.0; 95% CI=1.5-10.8). This association, particularly marked in patients who were not homozygous for M694V (34.0% vs. 11.6%), was independent of SAA1-allelic variations. Polymorphisms in the SAA2 or APOE gene did not appear to influence susceptibility to renal amyloidosis. Overall, these data, which provide new insights into the pathophysiology of FMF, demonstrate that susceptibility to renal amyloidosis in this Mendelian disorder is influenced by at least two MEFV-independent factors of genetic origin-SAA1 and sex-that act independently of each other.     

Complex formation dynamics of native and mutated pyrin's B30.2 domain with caspase‐1

Pyrin protein is the product of the MEFV gene, mutations in which cause manifestation of familial Mediterranean fever (FMF). Functions of pyrin are not completely clear. The secondary structure of the pyrin is represented with four domains and two motifs. Mutations p.M680I, p.M694V, p.M694I, p.K695R, p.V726A, and p.A744S, which are located in the B30.2 domain of pyrin protein, are responsible for manifestation of the most common and severe forms of FMF. All the domains and the motifs of pyrin, are directly or indirectly, involved in the protein–protein interaction with proteins of apoptosis and regulate the cascade of inflammatory reactions, which is impaired due to pyrin mutations. It is well known, that malfunction of the pyrin‐caspase‐1 complex is the main reason of inflammation during FMF. Complete tertiary structure of pyrin and the effects of mutations in it are experimentally not studied yet. The aim of this study was to identify possible effects of the abovementioned mutations in the B30.2 domain tertiary structure and to determine their potential consequences in formation of the B30.2‐caspase‐1 complex. Using in silico methods, it was found, that these mutations led to structural rearrangements in B30.2 domain tertiary structure, causing shifts of binding sites and altering the interaction energy between B30.2 and caspase‐1.