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.

Initial description of the human NLRP3 promoter.

Mutations in NLRP3 (CIAS1) are identified in a continuum of related inflammatory disorders, known as cryopyrinopathies since NLRP3 codes for the protein cryopyrin. Approximately 40% of patients with classic presentation lack mutations in the coding region of NLRP3 suggesting heterogeneity or epigenetic factors. Cryopyrin is a key regulator of proinflammatory cytokine release. Therefore, variations in the NLRP3 promoter sequence may have effects on disease state in patients with cryopyrinopathies and other inflammatory diseases. In this report, we confirmed three 5'-untranslated region splice forms with two separate transcriptional start sites, and identified potential promoter regions and six new DNA promoter variants. One variant is unique to a mutation negative cryopyrinopathy patient and increases in vitro gene expression. Additional studies can now be performed to further characterize the NLRP3 promoter and sequence variants, which will lead to better understanding of the regulation of NLRP3 expression and its role in disease.

Familial Mediterranean fever (FMF) and beyond: a new horizon. Fourth International Congress on the Systemic Autoinflammatory Diseases held in Bethesda, USA, 6-10 November 2005.

Autoinflammatory diseases are characterised by seemingly unprovoked inflammation. They can be categorised as: hereditary (monogenic) autoinflammatory diseases, complex (polygenic/multifactorial) autoinflammatory diseases, and diseases where the course is affected by mutations in the defined autoinflammatory disease genes. Identification of the inflammatory pathways involved has opened up new areas of research which have implications for the treatment of these disorders and the pathogenesis of common inflammatory diseases.

Autoinflammatory syndromes.

The autoinflammatory disorders are a new and expanding classification of inflammatory diseases characterized by recurrent episodes of systemic inflammation in the absence of pathogens, autoantibodies or antigen specific T cells. These disorders are caused by primary dysfunction of the innate immune system, without evidence of adaptive immune dysregulation. Innate immune abnormalities include aberrant responses to pathogen associated molecular patterns (PAMPs) like lipopolysaccharide and peptidoglycan, prominent neutrophilia in blood and tissues, and dysregulation of inflammatory cytokines (IL-1beta, TNF-alpha) or their receptors. The autoinflammatory diseases comprise both hereditary (Familial Mediterranean Fever, FMF; Mevalonate Kinase Deficiency, MKD; TNF Receptor Associated Periodic Syndrome, TRAPS; Cryopyrin Associated Periodic Syndrome, CAPS; Blau syndrome; Pyogenic sterile Arthritis, Pyoderma gangrenosum and Acne syndrome, PAPA; Chronic Recurrent Multifocal Osteomyelitis, CRMO) and multifactorial (Crohn's and Behçet's diseases) disorders. Mutations responsible for FMF, TRAPS, CAPS, PAPA are in proteins involved in modulation of inflammation and apoptosis.

The clinical course of a child with CINCA/NOMID syndrome improved during and after treatment with thalidomide.

Chronic, infantile, neurological, cutaneous, and articular (CINCA) syndrome, also known as neonatal-onset multisystem inflammatory disease (NOMID), is a rare autosomal dominant inherited disease. It is characterized by a persistent rash with onset during the neonatal period, neurological and ocular manifestations, and articular involvement with abnormal ossification. Mutations within the CIAS1 gene are found in up to 60% of CINCA cases, but the exact underlying pathogenetic mechanisms causing this disorder are still unclear. Although the interleukin-1 (IL-1) receptor antagonist anakinra (rHuIL-1Ra) has recently been reported to be effective, no formal recommended treatment protocols exist thus far. Herein, we describe a 17-year-old girl with CINCA for whom numerous medication trials had been unsuccessful. After the introduction of thalidomide, the symptoms of arthropathy improved dramatically even months after the medication was discontinued by the patient. We propose that thalidomide can be beneficial in select patients with CINCA syndrome.

Expression and regulation of cryopyrin and related proteins in rheumatoid arthritis synovium.

BACKGROUND: Rheumatoid arthritis (RA) synovium is characterised by enhanced NF-kappaB activity and proinflammatory cytokines. Cryopyrin (CIAS-1, NALP-3, PYPAF-1) has been shown to regulate NF-kappaB and caspase-1 activation. OBJECTIVE: To study the expression of cryopyrin, its effector molecule ASC, and its putative antagonist pyrin in RA and osteoarthritis (OA) synovium, and the main two cellular constituents of synovial lining, cultured fibroblast-like synoviocytes (FLS) and macrophages. METHODS: FLS and macrophages were cultured in the presence of inflammatory mediators. Real time polymerase chain reaction was used to quantify message levels in synovial biopsy specimens and cells. In situ hybridisation was employed to localise expression of cryopyrin mRNA. RESULTS: Cryopyrin mRNA was raised in RA synovium and detected in both lining and sublining regions. FLS from RA and OA tissue expressed low baseline levels of cryopyrin transcripts that were induced by tumour necrosis factor alpha (TNFalpha). In contrast, macrophages differentiated in vitro expressed relatively high cryopyrin levels, which were further induced by TNFalpha, but not by interleukin 1beta. ASC mRNA levels were comparable in RA and OA tissue, FLS, and macrophages, and were depressed by TNFalpha in macrophages. Pyrin expression was higher in RA synovium than in OA tissue, and virtually undetectable in FLS but high in macrophages where it was unchanged by TNFalpha treatment. CONCLUSION: These results suggest that enhanced cryopyrin levels in RA synovium are due to a greater numbers of tissue macrophages, and demonstrate transcriptional regulation of cryopyrin in a chronic inflammatory disease.

Allelic variants in genes associated with hereditary periodic fever syndromes as susceptibility factors for reactive systemic AA amyloidosis.

We investigated the hypothesis that low-penetrance mutations in genes (TNFRSF1A, MEFV and NALP3/CIAS1) associated with hereditary periodic fever syndromes (HPFs) might be risk factors for AA amyloidosis among patients with chronic inflammatory disorders, including rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), Crohn's disease, undiagnosed recurrent fevers and HPFs themselves. Four of 67 patients with RA plus amyloidosis had MEFV variants compared with none of 34 RA patients without amyloid (P value=0.03). The E148Q variant of MEFV was present in two of the three patients with TNF receptor-associated periodic syndrome (TRAPS) complicated by amyloid in two separate multiplex TRAPS families containing 5 and 16 affected members respectively, and the single patient with Muckle-Wells syndrome who had amyloidosis was homozygous for this variant. The R92Q variant of TNFRSF1A was present in two of 61 JIA patients with amyloidosis, and none of 31 nonamyloidotic JIA patients. No HPF gene mutations were found in 130 healthy control subjects. Although allelic variants in HPFs genes are not major susceptibility factors for AA amyloidosis in chronic inflammatory disease, low-penetrance variants of MEFV and TNFRSF1A may have clinically significant proinflammatory effects.

Mutation of a new gene encoding a putative pyrin-like protein causes familial cold autoinflammatory syndrome and Muckle-Wells syndrome.

Familial cold autoinflammatory syndrome (FCAS, MIM 120100), commonly known as familial cold urticaria (FCU), is an autosomal-dominant systemic inflammatory disease characterized by intermittent episodes of rash, arthralgia, fever and conjunctivitis after generalized exposure to cold. FCAS was previously mapped to a 10-cM region on chromosome 1q44 (refs. 5,6). Muckle-Wells syndrome (MWS; MIM 191900), which also maps to chromosome 1q44, is an autosomal-dominant periodic fever syndrome with a similar phenotype except that symptoms are not precipitated by cold exposure and that sensorineural hearing loss is frequently also present. To identify the genes for FCAS and MWS, we screened exons in the 1q44 region for mutations by direct sequencing of genomic DNA from affected individuals and controls. This resulted in the identification of four distinct mutations in a gene that segregated with the disorder in three families with FCAS and one family with MWS. This gene, called CIAS1, is expressed in peripheral blood leukocytes and encodes a protein with a pyrin domain, a nucleotide-binding site (NBS, NACHT subfamily) domain and a leucine-rich repeat (LRR) motif region, suggesting a role in the regulation of inflammation and apoptosis.

Familial cold autoinflammatory syndrome: phenotype and genotype of an autosomal dominant periodic fever.

BACKGROUND: Familial cold autoinflammatory syndrome (FCAS), commonly known as familial cold urticaria, is a rare autosomal dominant inflammatory disorder with episodic symptoms precipitated by exposure to cold. OBJECTIVE: The goal of this study was to formulate clinical diagnostic criteria for FCAS in a large cohort in whom the diagnosis of FCAS was supported by genetic linkage to chromosome 1q44. METHODS: We assessed 45 affected and 68 unaffected members from 6 American families. DNA analysis was performed to confirm linkage to chromosome 1q44. Clinical characteristics were determined by means of analysis of detailed questionnaires and medical histories. RESULTS: Pedigree and genetic analyses confirmed autosomal dominant transmission and linkage to chromosome 1q44 in all families. The most consistent symptoms during attacks were rash (100%), fever (93%), arthralgia (96%), and conjunctivitis (84%). Age of onset was within the first 6 months of life in 95% of affected subjects. The average delay between cold exposure and onset of symptoms was 2.5 hours, and the average duration of an episode was 12 hours. Renal disease with amyloidosis occurs infrequently in FCAS (2%). CONCLUSION: The most consistent clinical characteristics of FCAS that discriminate it from other periodic fevers are association with cold exposure, conjunctivitis, age of onset, duration of episodes, and an autosomal dominant inheritance pattern. On the basis of the analysis of genotype and phenotype of FCAS, we formulated clinical diagnostic criteria that can be used to distinguish FCAS from other hereditary periodic fever syndromes.

Development of an experimental paradigm in which to examine human learning using two computer-based formats.

Computer-based self-instructional programs are frequently promoted as means to augment or replace the traditional anatomy curricula taught in medical schools. These programs may range from static slide shows to fully immersive virtual environments. However, the impact of these learning technologies on knowledge acquisition, and their comparative cost/benefit to education remain unclear. As a consequence, we are embarking on a series of experiments to compare knowledge acquisition and the meaningful use of information among students who are learning anatomy using one of two different computer-based self-instructional formats. These studies will be based on a specially developed learning module on basic lung anatomy; they will utilize a variety of assessment tools to measure factual knowledge, conceptual understanding of spatial-anatomic relationships, and the ability to apply newly acquired knowledge of anatomy to clinical problem-solving scenarios. The primary object of this paper is to describe the design and development of the underlying test module and to outline the two computer-based formats that will be evaluated. The virtual reality (VR) environment, UCSD's Anatomic VisualizeR, provides dynamic access to 3-dimensional polygonal models of the lesson content and supports student-centered exploration and learning. The multimedia environment, Microsoft PowerPoint, provides a structured presentation of the lesson content and illustrates important anatomic structures through the use of 2-dimensional images derived by screen captures of models available in the VR learning module. This paper also provides an overview of the first experiment in the series, a pilot study using first-year medical students without previous participation in a medical school anatomy curriculum. For this study, students will be prospectively randomized into two groups, each group learning the lung anatomy lesson using one of the computer-based formats described. Immediate knowledge retention will be measured by asking students to complete the assessment instrument immediately after completing their learning module. The results of the pilot study will be used to refine and improve the design of the remainder of studies planned in this experimental series.

Humoral immunodeficiency with facial dysmorphology and limb anomalies: a new syndrome.

We report a 6 year old girl with an isolated humoral immune deficiency and a unique combination of dysmorphic features. Physical findings include microcephaly, micrognathia, sickle shaped eyebrows, hypoplastic alae nasi, thenar hypoplasia, partial 4-5 syndactyly of toes, recessed great toes, anterior anus, and hypoplastic labia minora. Radiographic findings include triphalangeal thumbs and hypoplastic first metatarsals. She has postnatal growth retardation and her development is substantially slower than her twin's. Her clinical course has been complicated by recurrent sinopulmonary infections and pneumococcal bacteraemia. Laboratory evaluation revealed hypogammaglobulinaemia, absent B cells, and a 46,XX karyotype. A review of the literature and the London Dysmorphology Database did not produce any recognizable syndromes that match her constellation of findings. She may represent a unique syndrome of unknown etiology.

Identification of a locus on chromosome 1q44 for familial cold urticaria.

Familial cold urticaria (FCU) is a rare autosomal dominant inflammatory disorder characterized by intermittent episodes of rash with fever, arthralgias, conjunctivitis, and leukocytosis. These symptoms develop after generalized exposure to cold. Some individuals with FCU also develop late-onset reactive renal amyloidosis, which is consistent with Muckle-Wells syndrome. By analyzing individuals with FCU from five families, we identified linkage to chromosome 1q44. Two-point linkage analysis revealed a maximum LOD score (Zmax) of 8.13 (recombination fraction 0) for marker D1S2836; multipoint linkage analysis identified a Zmax of 10. 92 in the same region; and haplotype analysis defined a 10.5-cM region between markers D1S423 and D1S2682. Muckle-Wells syndrome was recently linked to chromosome 1q44, which suggests that the two disorders may be linked to the same locus.

Cultural safety and renal care.

The Maori are the indigenous people of New Zealand. They and other Polynesian peoples who have migrated here in more recent times are over represented in our health statistics in ways that are of concern to New Zealand health care providers. Maori and Polynesian have higher rates of infant mortality, lung cancer, mental illness and, pertinent to this discussion, higher rates of diabetes and End Stage Renal Failure. Some of the issues raised by these statistics are the subject of my presentation today.

Mast cell adenosine induced calcium mobilization via Gi3 and Gq proteins.

Adenosine is an important mediator of mast cell secretory responses. Adenosine appears to act through one or more adenosine receptor subtypes to activate several signal transduction pathways; however, the specific mechanisms involved are not clearly defined. We studied the pathways involved in adenosine receptor-mediated calcium fluxes in RBL-2H3 cells, a mucosal mast cell-like line. The role of endogenous heterotrimeric G proteins in adenosine mediated calcium mobilization was investigated by microinjection of inhibitory antibodies that block specific G protein subtype function. The calcium transients associated with adenosine and antigen stimulation were compared in noninjected cells and cells that were microinjected with affinity purified neutralizing antibodies to the alpha subunits of Gi3, Gq, or Gs. The percentage of cells responding to adenosine was decreased in the presence of antibodies to Gi3 and Gq, but not Gs. Pertussis toxin decreased the percentage of cells responding to adenosine, but not antigen. These studies demonstrated a functional requirement for the pertussis toxin sensitive Gi3 protein and the pertussis toxin insensitive Gq protein in adenosine mediated calcium mobilization in mast cells.

Developing a virtual reality-multimedia system for anatomy training.

The University of California, San Diego, School of Medicine's Learning Resources Center is developing a prototype next-generation application for anatomy education which combines virtual reality and multimedia curricular resources. The anatomy lesson utilizes polygon-based 3-D models of the hepatobiliary system created by BioGraphics Inc. of Fort Collins, Colorado which were derived from the National Library of Medicine's Visible Human Project Dataset. This article describes the needs assessment, learning objectives, and preliminary design of the current prototype. The multivariate design, the development strategy for implementing functionalities, and the engineering of critical software interface components are also outlined.

IMED: the development of a consortium.

The California Consortium for Informatics in Medical Education and Development began in 1990 upon the recommendation of the academic deans of eight California medical schools. It provides one model of how consortia can promote the development, evaluation, dissemination, and utilization of technology-based medical education.