Disease course and treatment effects of a JAK inhibitor in a patient with CANDLE syndrome.

BACKGROUND: CANDLE syndrome (an acronym for Chronic Atypical Neutrophilic Dermatosis with Lipodystrophy and Elevated Temperature) is a recently described rare autosomal recessive disorder charaterized by systemic autoinflammation. Clinical manifestations include presentation in the first year of life, episodes of fever accompanied by erythematous skin lesions, progressive lipodystrophy, violaceous periorbital swelling and failure to thrive. This syndrome is caused by loss of function mutations and malfunction of the immunoproteasome complex. Most patients have biallelic mutations in the PSMB8 gene that encodes the ß5i catalytic subunit of the immunoproteasome. Examples of digenic inheritance have been also described in CANDLE. CANDLE patients have strong type I interferon gene expression signature and they are responsive to treatment with JAK inhibitors. However, possible serious side-effects remain a concern. Here, we report another patient with CANDLE whose disease activity was well controlled by the treatment with baricitinib. CASE PRESENTATION: We report a Bulgarian patient of the Turkish ancestry who carries biallelic mutations in the PSMB8 gene: p.Ala92Val and p.Lys105Gln. The pathogenic variant p.Ala92Val has not been previously described in patients with CANDLE. We also comment on the unusual feature in this patient, nephrolithiasis, that has not been described in other patients, however it might be related to the positive family history for kidney stones. We have treated the patient with the JAK inhibitor baricitinib for the past year and we observed a significant amelioration of his inflammatory episodes, skin and joint manifestations, and improvements in physical activities and growth. The treatment with glucocorticoids (GC) was completely discontinued. No side effects have been observed, however they remain in consideration for a life-long therapy of this disease. CONCLUSIONS: CANDLE should be suspected in patients with early-onset systemic inflammatory disease and prominent skin manifestations. Molecular testing can confirm the clinical diagnosis and is very important in guiding therapies. Treatment with JAK inhibitors is highly efficacious and appears to be safe in children with CANDLE and other intereforonopathies.

Clinical and Molecular Phenotypes of Low-Penetrance Variants of NLRP3: Diagnostic and Therapeutic Challenges.

OBJECTIVE: Cryopyrin-associated periodic syndromes (CAPS) result from gain-of-function mutations in the NLRP3 gene, which causes excessive release of interleukin-1ß (IL-1ß) and systemic inflammation. While pathogenetic NLRP3 variant phenotypes are well-characterized, low-penetrance NLRP3 variants represent a significant clinical challenge. The aims of this study were to determine the clinical phenotype, the in vitro biologic phenotype, and the effect of anti-IL-1 treatment in patients with low-penetrance NLRP3 variants. METHODS: A multicenter study of consecutive symptomatic patients with low-penetrance NLRP3 variants recruited from 7 centers between May 2012 and May 2013 was performed. The observed findings were transferred into a study database, from which they were extracted for analysis. Controls were patients with a known pathogenetic NLRP3 variant. Clinical presentation and CAPS markers of inflammation were captured. Functional assays of inflammasome activation, including caspase 1 activity, NF-κB release, cell death, and IL-1ß release, were performed. Treatment effects of IL-1 were determined. Comparisons between low-penetrance and pathogenetic NLRP3 variants were performed. RESULTS: The study included 45 patients, 21 of which were female (47%); 26 of the patients (58%) were children. NLRP3 low-penetrance variants identified in the patients were Q703K (n = 19), R488K (n = 6), and V198M (n = 20). In the controls, 28 had pathogenetic NLRP3 variants. Patients with low-penetrance NLRP3 variants had significantly more fever (76%) and gastrointestinal symptoms (73%); eye disease, hearing loss, and renal involvement were less common. Functional inflammasome testing identified an intermediate phenotype in low-penetrance NLRP3 variants as compared to wild-type and pathogenetic NLRP3 variants. All treated patients responded to IL-1 inhibition, with complete response documented in 50% of patients. CONCLUSION: Patients with low-penetrance NLRP3 variants display a distinct clinical phenotype and an intermediate biologic phenotype, including IL-1ß and non-IL-1ß-mediated inflammatory pathway activation.

Guidelines for the genetic diagnosis of hereditary recurrent fevers.

Hereditary recurrent fevers (HRFs) are a group of monogenic autoinflammatory diseases characterised by recurrent bouts of fever and serosal inflammation that are caused by pathogenic variants in genes important for the regulation of innate immunity. Discovery of the molecular defects responsible for these diseases has initiated genetic diagnostics in many countries around the world, including the Middle East, Europe, USA, Japan and Australia. However, diverse testing methods and reporting practices are employed and there is a clear need for consensus guidelines for HRF genetic testing. Draft guidelines were prepared based on current practice deduced from previous HRF external quality assurance schemes and data from the literature. The draft document was disseminated through the European Molecular Genetics Quality Network for broader consultation and amendment. A workshop was held in Bruges (Belgium) on 18 and 19 September 2011 to ratify the draft and obtain a final consensus document. An agreed set of best practice guidelines was proposed for genetic diagnostic testing of HRFs, for reporting the genetic results and for defining their clinical significance.

The regulation of MEFV expression and its role in health and familial Mediterranean fever.

Familial Mediterranean fever (FMF) is a hereditary recurrent fever associated with mutations in the gene MEFV encoding pyrin. It is expressed mainly in neutrophils and macrophages, and modulates the production of the potent pro-inflammatory cytokine interleukin-1ß through regulation of nuclear factor-κB and caspase-1. The MEFV gene expression depends on multiple levels of regulation. Sequence variants located in the promoter and at the 3'-untranslated region of the gene modulate this expression. Two studies demonstrated decreased mRNA levels in FMF patients compared with healthy subjects, whereas two others found no significant differences. The diverse experimental settings may have resulted in variable quantification of the 15 splice variants that have been identified recently. Some of these isoforms are regulated by nonsense-mediated decay in both cell- and transcript-specific manner, and may be differentially translated in THP1 cells. In addition, pyrin may be cleaved by caspase 1. The full-length pyrin was less abundant than the cleaved fragment in mononuclear cells from FMF patients than in controls, whereas the opposite was observed in granulocytes. Altogether, the regulation of MEFV expression is more complex than anticipated in both physiological and pathological conditions. Its deregulation is likely to alter the inflammasome function and subsequently result in uncontrolled inflammation as seen in FMF.

A novel mutation in TNFRSF1A associated with overlapping features of tumor necrosis factor receptor-associated periodic syndrome and hyper-IgD syndrome.

We describe a 10-year-old child with a novel mutation, c.352A>G/p.Thr118Ala (T89A) in the tumour necrosis factor receptor superfamily 1A (TNFRSF1A) gene. The patient presented with periodic fevers beginning at 2 years of age. He had overlapping clinical and laboratory features of tumour necrosis factor receptor-associated periodic syndrome (TRAPS) and hyper-IgD syndrome (HIDS). This patient expands the clinical and genetic spectrum of TRAPS.

Clinical features and functional significance of the P369S/R408Q variant in pyrin, the familial Mediterranean fever protein.

OBJECTIVES: Familial Mediterranean fever (FMF) is caused by mutations in MEFV, which encodes pyrin. The nature of substitutions P369S and R408Q in exon 3 remains unclear. Exon 3 encoding pyrin's B-box domain is necessary for interactions with proline serine threonine phosphatase interacting protein 1 (PSTPIP1). The aim was to characterise the phenotype of patients with these substitutions and to determine their functional significance. METHODS: A database of genetic tests undertaken at the US National Institutes of Health was interrogated. Symptoms and signs were classified according to Tel-Hashomer criteria. Coimmunoprecipitation techniques were employed to determine the variants' effects on pyrin/PSTPIP1 interactions. RESULTS: A total of 40 symptomatic and 4 asymptomatic family members with these substitutions were identified. P369S and R408Q were found in cis, and cosegregated in all patients sequenced. Clinical details were available on 22 patients. In all, 5 patients had symptoms and signs fulfilling a clinical diagnosis of FMF, and 15 received colchicine. In patients not achieving the criteria, trials of anti-tumour necrosis factor (TNF) agents resulted in partial or no benefit; resolution of symptoms was noted in those receiving anakinra. The carrier frequency was higher in the patient cohort than in controls but was not statistically significant. Coimmunoprecipitation studies demonstrated that these pyrin variants did not affect binding to PSTPIP1. CONCLUSIONS: P369S/R408Q substitutions are associated with a highly variable phenotype, and are infrequently associated with typical FMF symptoms, however a trial of colchicine is warranted in all. Functional and modelling studies suggest that these substitutions do not significantly affect pyrin's interaction with PSTPIP1. This study highlights the need for caution in interpreting genetic tests in patients with atypical symptoms.

An international external quality assessment for molecular diagnosis of hereditary recurrent fevers: a 3-year scheme demonstrates the need for improvement.

Hereditary recurrent fevers (HRF) are rare diseases caused by molecular defects in genes involved in the regulation of innate immunity. Sixty-seven international laboratories participated in an external quality assessment (EQA) scheme, which was developed to appraise the accuracy of genetic testing. Reports were evaluated for the 12 items recommended by the OECD (Organisation for Economic Co-Operation and Development) guidelines for molecular diagnostics. The best documented items were the name of the gene, the biologist, or the patient, whereas information on the test and screening limits, and clinical interpretation of the disease inheritance were scarcely provided. The mutation nomenclature was incomplete in about 70% of the cases. In the first 2 years of EQA, we identified almost 30% genotyping error rate, which decreased markedly in the last year. The combined performance on the basis of the correct identification of all genotypes by a given laboratory in all the 3 years was only 40%, showing a critical need for improvement.

Familial Mediterranean Fever in Crete: a genetic and structural biological approach in a population of 'intermediate risk'.

Familial Mediterranean Fever (FMF) is an autosomal, recessively inherited disease, characterized by recurrent and short attacks of fever with serosal inflammation that are caused by mutations in MEFV gene that encodes pyrin protein. To date, more than 70 disease-associated mutations have been identified, almost all of them representing missense nucleotide changes. FMF is very common among patients with Mediterranean ancestry, although the exact prevalence is not yet known, Greeks are considered to be at 'intermediate risk'. In the present study, we studied FMF patients in natives of Crete, a population sharing a common genetic and cultural background. The spectrum of MEFV gene mutations in 71 patients as well as 158 healthy controls was studied by performing a molecular analysis focused on the 12 most frequent FMF-associated mutations. We found that 59 of 71 (83.1%) FMF patients had at least one MEFV mutation, five patients were homozygotes and 54 heterozygotes for FMF-associated mutations. No mutations were detected in 12 patients (16.9%). As in high-risk populations, common MEFV mutations were found in Cretan FMF patients, with the M694V being the most penetrant. M694V and M694I mutations were associated with severe phenotypes, with many patients presenting with uncommon clinical manifestations such as erysipelas-like erythema or renal disturbances. Of interest, 20 (37%) of our heterozygous FMF patients presented with a severe phenotype. Population genetics analysis showed an FMF carrier frequency in healthy Cretan population of approximately 6% (1:17) and places Cretans closer to the Western rather than Eastern populations of the Mediterranean basin. Finally, we constructed a three-dimensional model showing the interaction of the PRYSPRY domain of pyrin with caspase-1 onto which we mapped MEFV mutations, classified according to disease severity. In this model, the 'flexible loops' of caspase-1 appear to have no access to some positions that have been previously associated with mild disease, suggesting that alternative pathogenic pathways leading to FMF need to be explored.

Mutational analysis of the PRYSPRY domain of pyrin and implications for familial mediterranean fever (FMF).

Familial Mediterranean fever (FMF) is an autosomal, recessively inherited disease, characterized by recurrent fever and serositis that affects mainly patients of the Mediterranean basin. The gene responsible for FMF, named MEFV, was cloned and several missense mutations were found to be responsible for the disease. Based on a recent molecular analysis of MEFV gene mutations in 43 patients from Crete aiming to correlate specific genotypes and clinical manifestations of FMF, we were prompted to construct a three-dimensional model (3-D model) of the PRYSPRY domain of pyrin. The majority of the known MEFV mutations located on this domain have been classified, according to disease severity, and localized on this 3-D model. The functional consequences of these mutations and their implications on disease severity are discussed. Moreover, we report a putative novel missense mutation, S702C, which we identified in exon 10 of the MEFV gene and localized on the constructed 3-D model.

Analysis of CARD15/NOD2 haplotypes fails to identify common variants associated with rheumatoid arthritis susceptibility.

OBJECTIVES: The CARD15/NOD2 gene product plays an important role in host response to bacterial lipopolysaccharides and bacterial muramyl dipeptide via activation of NF-kappaB in monocytes. Mutations in CARD15 are associated with Crohn's disease (CD), a chronic inflammatory bowel disease. In this study we sought to determine whether CD-associated mutations or any common variants of this gene might contribute to susceptibility to another chronic inflammatory disease, rheumatoid arthritis (RA). METHODS: We genotyped 376 Caucasian RA cases and 376 ethnically matched healthy controls for three CD-associated CARD15 mutations. We also genotyped these 752 individuals for 12 common CARD15 single nucleotide polymorphisms (SNPs), determined the linkage disequilibrium structure of the gene, and compared the frequencies of the common CARD15 haplotypes in the RA cases and controls. RESULTS: None of the CD-associated mutations or the CARD15 SNPs was associated with susceptibility to RA. We also found no significant difference in the frequencies of any of the common haplotypes of the CARD15 gene in RA patients and controls. Our haplotype analysis was consistent with earlier observations that all three CD-associated variants independently arose on the same ancestral haplotype. CONCLUSIONS: These data suggest that CARD15 variants are not associated with RA susceptibility.

Lack of evidence for an association between two genetic polymorphisms in the tumor necrosis factor receptor 1 gene and multiple sclerosis in Ashkenazi Jews.

Multiple sclerosis (MS) is a multifactorial disease with a documented genetic component. Recent experimental models suggested a role for the tumor necrosis factor receptor 1 (TNFR1) in the pathogenesis of the disease. We compared the frequency of two polymorphisms from TNFR1, located in exon 1 and intron 6, in 94 Jewish Ashkenazi MS patients and 83 healthy Ashkenazi controls. No significant differences were observed for both polymorphisms between the patients and the controls. These findings suggest that genetic variants in TNFR1 do not play a significant role in Ashkenazi Jews.

The tumor-necrosis-factor receptor-associated periodic syndrome: new mutations in TNFRSF1A, ancestral origins, genotype-phenotype studies, and evidence for further genetic heterogeneity of periodic fevers.

Mutations in the extracellular domain of the 55-kD tumor-necrosis factor (TNF) receptor (TNFRSF1A), a key regulator of inflammation, define a periodic-fever syndrome, TRAPS (TNF receptor-associated periodic syndrome [MIM 142680]), which is characterized by attacks of fever, sterile peritonitis, arthralgia, myalgia, skin rash, and/or conjunctivitis; some patients also develop systemic amyloidosis. Elsewhere we have described six disease-associated TNFRSF1A mutations, five of which disrupt extracellular cysteines involved in disulfide bonds; four other mutations have subsequently been reported. Among 150 additional patients with unexplained periodic fevers, we have identified four novel TNFRSF1A mutations (H22Y, C33G, S86P, and c.193-14 G-->A), one mutation (C30S) described by another group, and two substitutions (P46L and R92Q) present in approximately 1% of control chromosomes. The increased frequency of P46L and R92Q among patients with periodic fever, as well as functional studies of TNFRSF1A, argue that these are low-penetrance mutations rather than benign polymorphisms. The c.193-14 G-->A mutation creates a splice-acceptor site upstream of exon 3, resulting in a transcript encoding four additional extracellular amino acids. T50M and c.193-14 G-->A occur at CpG hotspots, and haplotype analysis is consistent with recurrent mutations at these sites. In contrast, although R92Q also arises at a CpG motif, we identified a common founder chromosome in unrelated individuals with this substitution. Genotype-phenotype studies identified, as carriers of cysteine mutations, 13 of 14 patients with TRAPS and amyloidosis and indicated a lower penetrance of TRAPS symptoms in individuals with noncysteine mutations. In two families with dominantly inherited disease and in 90 sporadic cases that presented with a compatible clinical history, we have not identified any TNFRSF1A mutation, despite comprehensive genomic sequencing of all of the exons, therefore suggesting further genetic heterogeneity of the periodic-fever syndromes.

The familial Mediterranean fever protein, pyrin, associates with microtubules and colocalizes with actin filaments.

Familial Mediterranean fever (FMF) is a recessive disorder characterized by episodes of fever and intense inflammation. FMF attacks are unique in their sensitivity to the microtubule inhibitor colchicine, contrasted with their refractoriness to the anti-inflammatory effects of glucocorticoids. The FMF gene, MEFV, was recently identified by positional cloning; it is expressed at high levels in granulocytes and monocytes. The present study investigated the subcellular localization of the normal gene product, pyrin. These experiments did not support previously proposed nuclear or Golgi localizations. Instead fluorescence microscopy demonstrated colocalization of full-length GFP- and epitope-tagged pyrin with microtubules; this was markedly accentuated in paclitaxel-treated cells. Moreover, immunoblot analysis of precipitates of stabilized microtubules with recombinant pyrin demonstrated a direct interaction in vitro. Pyrin expression did not affect the stability of microtubules. Deletion constructs showed that the unique N-terminal domain of pyrin is necessary and sufficient for colocalization, whereas disease-associated mutations in the C-terminal B30.2 (rfp) domain did not disrupt this interaction. By phalloidin staining, a colocalization of pyrin with actin was also observed in perinuclear filaments and in peripheral lamellar ruffles. The proposal is made that pyrin regulates inflammatory responses at the level of leukocyte cytoskeletal organization and that the unique therapeutic effect of colchicine in FMF may be dependent on this interaction. (Blood. 2001;98:851-859)

A single mutated MEFV allele in Israeli patients suffering from familial Mediterranean fever and Behçet's disease (FMF-BD).

Although familial Mediterranean fever (FMF) is an autosomal recessive disorder, preliminary partial mutation analysis suggested that about 60% of FMF patients, who also suffer from Behçet's disease (FMF-BD), have only a single mutated FMF gene (MEFV). In this study, the possibility that patients with FMF-BD may indeed be carriers of a single mutated MEFV is further analysed. The presence of mutations in the coding region of MEFV of eight patients with FMF-BD, representing six families with 47 members, was determined by sequencing. A possible role for the non-carrier chromosome and for BD in the expression of FMF in patients with a single mutated MEFV allele was determined by analysing the association between these variables and the presence of FMF in heterozygous kin. Sequence analysis revealed that all eight patients had indeed only one mutation in the coding region of MEFV. The patients' non-carrier chromosomes converged into three different MEFV haplotypes and were shared by heterozygous unaffected kin in five of six families. BD was found in 10 of 11 carriers with FMF vs one of 16 carriers without FMF (P < 0.001). These results suggest that FMF may be expressed in individuals harbouring only one coding mutation in MEFV. The findings argue against a role for the non-carrier chromosome in the induction of FMF, and suggest that the FMF phenotype in this cohort was associated with the simultaneous presence of BD. These findings may mirror a more generalised rule, that FMF may be precipitated in carriers of a single mutated FMF gene by factors unrelated to the other MEFV allele.

Episodic evolution of pyrin in primates: human mutations recapitulate ancestral amino acid states.

Familial Mediterranean fever (FMF; MIM 249100) is an autosomal recessive disease characterized by recurrent attacks of fever with synovial, pleural or peritoneal inflammation. The disease is caused by mutations in the gene encoding the pyrin protein. Human population studies have revealed extremely high allele frequencies for several different pyrin mutations, leading to the conclusion that the mutant alleles confer a selective advantage. Here we examine the ret finger protein (rfp) domain (which contains most of the disease-causing mutations) of pyrin during primate evolution. Amino acids that cause human disease are often present as wild type in other species. This is true at positions 653 (a novel mutation), 680, 681, 726, 744 and 761. For several of these human mutations, the mutant represents the reappearance of an ancestral amino acid state. Examination of lineage-specific dN/dS ratios revealed a pattern consistent with the signature of episodic positive selection. Our data, together with previous human population studies, indicate that selective pressures may have caused functional evolution of pyrin in humans and other primates.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) in a Dutch family: evidence for a TNFRSF1A mutation with reduced penetrance.

Mutations of the tumor necrosis factor receptor 1 (TNFRSF1A) gene underly susceptibility to a subset of autosomal dominant recurrent fevers (ADRFs). We report on a two-generation six-member Dutch family in which a novel R92P mutation and reduced plasma TNFRSF1A levels were found in all the children, including two who are unaffected. However, only the daughter proband and father exhibited a typical TNF-receptor associated periodic syndrome (TRAPS) phenotype. PCR-RFLP analysis revealed that the mutation was not present in 120 control chromosomes from unaffected Dutch individuals. As this R92P mutation is present in two unaffected carriers it appears to be less penetrant than previously reported TNFRSF1A mutations involving cysteine residues in the extracellular domains.

Unexpected and variable phenotypes in a family with JAK3 deficiency.

Mutations of the Janus kinase 3 (JAK3) have been previously described to cause an autosomal recessive variant of severe combined immunodeficiency (SCID) usually characterized by the near absence of T and NK cells, but preserved numbers of B lymphocytes (T-B+SCID). We now report a family whose JAK3 mutations are associated with the persistence of circulating T cells, resulting in previously undescribed clinical presentations, ranging from a nearly unaffected 18-year-old subject to an 8-year-old sibling with a severe lymphoproliferative disorder. Both siblings were found to be compound heterozygotes for the same deleterious JAK3 mutations: an A96G initiation start site mutation, resulting in a dysfunctional, truncated protein product and a G2775(+3)C mutation in the splice donor site sequence of intron 18, resulting in a splicing defect and a predicted premature stop. These mutations were compatible with minimal amounts of functional JAK3 expression, leading to defective cytokine-dependent signaling. Activated T cells in these patients failed to express Fas ligand (FasL) in response to IL-2, which may explain the accumulation of T cells with an activated phenotype and a skewed T cell receptor (TcR) Vbeta family distribution. We speculate that residual JAK3 activity accounted for the maturation of thymocytes, but was insufficient to sustain IL-2-mediated homeostasis of peripheral T cells via Fas/FasL interactions. These data demonstrate that the clinical spectrum of JAK3 deficiency is quite broad and includes immunodeficient patients with accumulation of activated T cells, and indicate an essential role for JAK3 in the homeostasis of peripheral T cells in humans.

Tumor necrosis factor receptor-associated periodic syndrome: a novel syndrome with cutaneous manifestations.

BACKGROUND: Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) is an inflammatory disorder characterized by prolonged episodes of periodic fever and localized inflammation and dominantly inherited mutations in TNFRSF1A, the gene encoding the 55-kDa tumor necrosis factor receptor. To our knowledge, the cutaneous pathologic characteristics of TRAPS have not been described previously. OBJECTIVES: To characterize the dermatologic manifestations of TRAPS by clinical, microscopic, and molecular methods, and to investigate its immunophenotype. DESIGN, SETTING, AND PATIENTS: At the National Institutes of Health Clinical Center, Bethesda, Md, a tertiary care referral center, 25 patients with a clinical and molecular diagnosis of TRAPS were evaluated clinically and 10 biopsy specimens of lesional skin were examined by light microscopy and immunohistochemistry. Patients were screened for mutations in TNFRSF1A, the gene coding for the p55 tumor necrosis factor receptor. MAIN OUTCOME MEASURES: Clinical, light microscopic, and immunohistochemical features. RESULTS: The skin eruption usually lasted 4 to 21 days (mean, 13 days). Of 25 patients, 21 (84%) presented with migratory erythematous macules and patches and 10 (40%) had edematous dermal plaques. Conjunctivitis, characterized by pain and redness and/or periorbital edema, was present in 11 patients (44%). Most patients had their first skin eruption during the first 2 years of life. All patients had fever associated with the skin eruption. Most patients had associated abdominal pain (22 [88%]) and myalgia (20 [80%]). Other symptoms included arthralgia (13 [52%]), pleuritic chest pain (10 [40%]), and headache (17 [68%]). Microscopic examination of 10 biopsy specimens of lesional skin showed a superficial and deep perivascular and interstitial infiltrate of lymphocytes and monocytes. None of the biopsy specimens showed multinucleated macrophages or granulomatous or leukocytoclastic vasculitis. The results of immunohistochemistry showed a perivascular infiltrate of CD3+, CD4+, CD8+, CD68+, CD79a-, and CD20- cells. All the mutations were missense mutations in exons 2 through 4 of TNFRSF1A, directly affecting the extracellular domain of the protein. CONCLUSIONS: TRAPS is characterized by a spectrum of dermatologic findings, including migratory patches, edematous plaques, periorbital edema, and/or conjunctivitis. TRAPS is characterized by a perivascular dermal infiltrate of lymphocytes and monocytes.

TNFRSF1A mutations and autoinflammatory syndromes.

The autoinflammatory syndromes are systemic disorders characterized by apparently unprovoked inflammation in the absence of high-titer autoantibodies or antigen-specific T lymphocytes. One such illness, TNF-receptor-associated periodic syndrome (TRAPS), presents with prolonged attacks of fever and severe localized inflammation. TRAPS is caused by dominantly inherited mutations in TNFRSF1A (formerly termed TNFR1), the gene encoding the 55 kDa TNF receptor. All known mutations affect the first two cysteine-rich extracellular subdomains of the receptor, and several mutations are substitutions directly disrupting conserved disulfide bonds. One likely mechanism of inflammation in TRAPS is the impaired cleavage of TNFRSF1A ectodomain upon cellular activation, with diminished shedding of the potentially antagonistic soluble receptor. Preliminary experience with recombinant p75 TNFR-Fc fusion protein in the treatment of TRAPS has been favorable.

Genotype-phenotype assessment of common genotypes among patients with familial Mediterranean fever.

OBJECTIVE: To study genotype-phenotype correlation for the 4 most common genotypes found among patients with familial Mediterranean fever (FMF). METHODS: Thirty patients with the M694V/M694V genotype, 32 with M694V/V726A genotype, 25 with M694V/E 148Q genotype, and 21 with V726A/V726A genotype were assessed for various clinical manifestations of FMF, and overall disease severity. RESULTS: Patients with the M694V/M694V genotype were found to have an earlier age of onset, higher frequency of joint involvement, higher frequency of erysipelas-like erythema, and required higher doses of colchicine to control the disease compared to the other 3 genotypes. CONCLUSION: The M694V/M694V genotype is associated with more severe disease compared to other common genotypes in patients with FMF.