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C1-inhibitor protects against brain ischemia-reperfusion injury via inhibition of cell recruitment and inflammation.

Previous studies demonstrated that C1-inhibitor (C1-INH), a complement and contact-kinin systems inhibitor, is neuroprotective in cerebral ischemia. To investigate the mechanism of this action, we evaluated the expression of neurodegeneration and inflammation-related factors in mice subjected to 2-h ischemia and 2 or 46 h reperfusion. C1-INH significantly dampened the mRNA expression of the adhesion molecules P-selectin and ICAM-1 induced by the ischemic insult. It significantly decreased the pro-inflammatory cytokine (TNF alpha, IL-18) and increased the protective cytokine (IL-6, IL-10) gene expression. C1-INH treatment prevented the decrease of NFH gene, a marker of cellular integrity and counteracted the increase of pro-caspase 3, an apoptosis index. Furthermore, C1-INH markedly inhibited the activation and/or recruitment of microglia/macrophage, as shown by immunohistochemistry. In conclusion, C1-INH exerts an anti-inflammatory and anti-apoptotic action on ischemia-reperfusion injury. Our present and past data support a major effect of C1-INH on cell recruitment from the vasculature to the ischemic site.

Animals↗

HAEdb: a novel interactive, locus-specific mutation database for the C1 inhibitor gene.

Hereditary angioneurotic edema (HAE) is an autosomal dominant disorder characterized by episodic local subcutaneous and submucosal edema and is caused by the deficiency of the activated C1 esterase inhibitor protein (C1-INH or C1INH; approved gene symbol SERPING1). Published C1-INH mutations are represented in large universal databases (e.g., OMIM, HGMD), but these databases update their data rather infrequently, they are not interactive, and they do not allow searches according to different criteria. The HAEdb, a C1-INH gene mutation database (http://hae.biomembrane.hu) was created to contribute to the following expectations: 1) help the comprehensive collection of information on genetic alterations of the C1-INH gene; 2) create a database in which data can be searched and compared according to several flexible criteria; and 3) provide additional help in new mutation identification. The website uses MySQL, an open-source, multithreaded, relational database management system. The user-friendly graphical interface was written in the PHP web programming language. The website consists of two main parts, the freely browsable search function, and the password-protected data deposition function. Mutations of the C1-INH gene are divided in two parts: gross mutations involving DNA fragments >1 kb, and micro mutations encompassing all non-gross mutations. Several attributes (e.g., affected exon, molecular consequence, family history) are collected for each mutation in a standardized form. This database may facilitate future comprehensive analyses of C1-INH mutations and also provide regular help for molecular diagnostic testing of HAE patients in different centers.

Angioedema↗

Mutation screening of the C1 inhibitor gene among Hungarian patients with hereditary angioedema.

Hereditary angioneurotic edema (HAE) is an autosomal dominant disorder characterized by episodic local subcutaneous and submucosal edema caused by the deficiency of activated C1 esterase inhibitor protein (C1-INH, type I (C1NH): reduced serum antigen level, type II: reduced activity and normal serum antigen level). The aim of the present study was to determine the disease-causing mutations in the C1INH gene (SERPING1) among Hungarian HAE-patients. The estimated number of affected HAE-families in Hungary is 40-50, out of which 26 families (type I:23, type II:3) managed in a single center were enrolled in the current study. To detect large deletions/insertions, we used Southern-blotting analysis followed by real time PCR based gene dosage analysis. In the absence of large structural changes, we employed direct sequencing covering the whole coding region and splicing sites of the C1INH gene. Large deletions were detected in 4/23 (17.4%) type I families. We found the g.16788C>T (p.Arg444Cys) mutation in each 3, type II HAE-families. In the remaining type I families, 13 previously unreported mutations (g.638G>A, g.2238C>T, g.2534_2535delCT, g.2579_2620del42, g.2533G>A, g.2695G>A, g.2696_2697insT, g.4467C>T, g.14224A>T, g.14107delA, g.16749_;16775dup, g.16810T>A, g.16885C>G) were detected in 16 families affecting primarily exon 3 (6/13) of the C1INH gene. In the 3 remaining families, known mutations were identified affecting primarily exon 8 (2/3).

Angioedema↗

C1 inhibitor gene expression in patients with hereditary angioedema: quantitative evaluation by means of real-time RT-PCR.

BACKGROUND: Hereditary angioedema (HAE) is caused by heterozygous defects in the C1 inhibitor (C1-INH) gene (SERPING1/C1NH). In patients' plasma C1-INH levels range between 5% and 30% of normal levels (ie, far from the 50% expected for an autosomal dominant defect). Most patients have antigenic and functional deficiency (type I HAE), and 15% have reduced C1-INH function but normal to increased antigen because of the presence of a dysfunctional protein (type II HAE). OBJECTIVE: We sought to contribute to the understanding of the pattern of C1-INH gene expression in patients with HAE. METHODS: We used real-time quantitative RT-PCR to measure C1-INH mRNA levels in PBMCs of 57 patients with HAE typed for mutations in the SERPING1/C1NH gene. RESULTS: Thirty-six different mutations were identified in genomic DNA. Compared with healthy control subjects, C1-INH mRNA was significantly and similarly reduced in patients with type I and type II HAE (40% and 47%, respectively; P <.0001). By means of direct sequencing of cDNAs, we found that 74% of patients with type I HAE carrying small mutations presented significant amounts of mutated transcripts at the mRNA level, suggesting that both allelic mRNA products were reduced to approximately 50%. In 4 patients carrying large deletions expected to fully inactivate expression from the mutant allele, C1-INH mRNA was 23% on average compared with that seen in control subjects, confirming that normal mRNA was strongly underexpressed. CONCLUSIONS: These new findings, combined with previous evidence of increased C1-INH consumption, might explain the plasma levels of normal C1-INH that are markedly less than the expected 50%.

Angioedema↗

Hereditary angioedema: a family study.

Hereditary angioedema (HAE) is a rare, life-threatening, autosomal dominant disease characterized by recurrent episodes of angioedema, and caused by a deficiency of the plasma protein C1-esterase inhibitor (C1-INH). Clinical manifestation of HAE may first develop during childhood but typically presents around puberty with nonpruritic and non-pitting edema of the subcutaneous and mucosal tissues. Up to now, there has been no published report of HAE case in Taiwan. We reported a 33 year-old female patient who had recurrent painful swelling of face and hands since 27 years of age. She first suffered from sudden onset of painful swelling of the eyelids and lips in August 1998 when she was pregnant for the first time. Subsequently, similar episodes recurred for a few times. Her blood test disclosed that her C3 and C4 were 125 mg/dl and 6 mg/dl, respectively. Her uncle died of laryngeal edema at the age of 30 years. Her father and elder brother also had the similar history of recurrent facial and hand swelling. The C4 levels of her elder brother were 6 mg/dl and 13.3 mg/dl on two separate occasions. The C1-INH antigen serum level and functional assay of the index patient and ten other family members were studied. A total of seven members of the family were confirmed to have type 1 HAE as evidenced by the low C4 and low C1-INH antigenic level and functional activity. Two of the seven cases were asymptomatic up to the date of our report.

Adult↗

C1-inhibitor reduces the ischaemia-reperfusion injury of skeletal muscles in mice after aortic cross-clamping.

BACKGROUND: Both C1-inhibitor (C1-INH) and antibodies against the CD18 adhesion molecule have been shown to reduce ischaemia-reperfusion injuries. The objective of this study was to investigate the effect of increased ischaemia times and to determine whether inhibiting C1 or blocking the CD18 function was protective in skeletal muscle ischaemia-reperfusion injury after aortic cross-clamping. MATERIALS AND METHODS: BALB/c mice were subjected to aortic cross-clamping below the renal artery for 60, 75 or 105 min, followed by 3 h of reperfusion. Two-thirds of a total dose of anti-CD18 antibody (40 mg/kg) or human C1-INH (1,000 IU/kg) was given by intraperitoneal injection before ischaemia and one-third immediately after the clamping. Creatine kinase (CK) in the plasma was used as an indicator of muscle injury severity. RESULTS: There was a consistent rise in the plasma CK concentration proportional to the length of ischaemia (P < 0.0005). C1-INH treatment significantly (P = 0.012) reduced the plasma CK for the ischaemia times of 75 and 105 min. The anti-CD18 antibody did not have any effect, as demonstrated by the CK values that were similar to controls (P = 0.836). CONCLUSION: The data support a beneficial role for C1-INH in the treatment of ischaemia-reperfusion injuries of skeletal muscles.

Animals↗

C1 inhibitor: molecular and clinical aspects.

C1 inhibitor (C1-INH) is a serine protease inhibitor (serpins) that inactivates several different proteases in the complement, contact, coagulation, and fibrinolytic systems. By its C-terminal part (serpin domain), characterized by three beta-sheets and an exposed mobile reactive loop, C1-INH binds, and blocks the activity of its target proteases. The N-terminal end (nonserpin domain) confers to C1-INH the capacity to bind lipopolysaccharides and E-selectin. Owing to this moiety, C1-INH intervenes in regulation of the inflammatory reaction. The heterozygous deficiency of C1-INH results in hereditary angioedema (HAE). The clinical picture of HAE is characterized by bouts of local increase in vascular permeability. Depending on the affected site, patients suffer from disfiguring subcutaneous edema, abdominal pain, vomiting and/or diarrhoea for edema of the gastrointestinal mucosa, dysphagia, and dysphonia up to asphyxia for edema of the pharynx and larynx. Apart from its genetic deficiency, there are several pathological conditions such as ischemia-reperfusion, septic shock, capillary leak syndrome, and pancreatitis, in which C1-INH has been reported to either play a pathogenic role or be a potential therapeutic tool. These potential applications were identified long ago, but controlled studies have not been performed to confirm pilot experiences. Recombinant C1-INH, produced in transgenic animals, has recently been produced for treatment of HAE, and clinical trials are in progress. We can expect that the introduction of this new product, along with the existing plasma derivative, will renew interest in exploiting C1-INH as a therapeutic agent.

Angioedema↗

Detection of C1 inhibitor (SERPING1/C1NH) mutations in exon 8 in patients with hereditary angioedema: evidence for 10 novel mutations.

Hereditary angioedema (HAE) is caused by mutations in the C1 inhibitor gene (SERPING1, C1NH) and the result is C1 inhibitor deficiency, either in levels or function. We have searched exon 8 for mutations by direct sequencing and analyzed the rest of the exons by SSCP in 87 Spanish families affected by HAE. Out of 87 screened families, we have detected exon 8 mutations in 26. Among these, 17 different mutations were identified: 14 point mutations and 3 frameshift. Seven of the point mutations and the three frameshift were not previously reported. Mutations were: S438P; R444P; V451G; W460X; V468D; G471E; X479R; S417fsX427; I440fsX450; E429fsX450. The rest of the families presented previously reported mutations, 5 missense and two nonsense. In none of the 26 families was an additional change identified in the rest of the exons by SSCP, and, in 20 out of the 22 families with point mutation, we verified that the mutation did not affect a healthy relative. Seven of these families had no history of the disease, and in five of them we were able to verify that the progenitors did not have the mutation. Therefore, they were de novo mutations.

Angioedema↗

C1 inhibitor infusion modifies platelet activity in hereditary angioedema patients.

CONTEXT: C1 inhibitor (C1-INH) is an alpha2-globulin that blocks esterolytic activity of the first component of the classic complement cascade. The alpha-granules of normal human platelets also contain C1-INH, which is expressed on the platelet surface during platelet secretion in healthy patients, but it is clearly reduced in patients with hereditary angioedema (HAE). OBJECTIVE: To evaluate the effects of in vivo C1-INH concentrate infusion on platelet responsiveness and coagulation system activity in patients with HAE. DESIGN: Assessment of the platelet activity and plasma levels of C1-INH, activated factor XII (XIIa), and prothrombin fragment F1.2 (F1.2) before and after infusion of 15 U/kg of C1-INH concentrate. PATIENTS: In 6 patients (4 men and 2 women), HAE was diagnosed according to the accepted clinical and laboratory criteria. MEASUREMENTS: Platelet aggregation (final concentrations: adenosine diphosphate, 0.5, 1.25, and 2.5 microM; collagen, 5 microg/mL), C1-INH antigen (radial immunodiffusion), C1-INH activity (chromogenic substrates), and XIIa and F1.2 (enzyme-linked immunosorbent assay). RESULTS: After C1-INH infusion, we observed a prompt increase of C1-INH level and a slow return toward its plasma preinfusion values within 4 to 7 days, a significant decrease of both adenosine diphosphate- and collagen-induced platelet aggregation versus preinfusion values (maximum after 1-2 days; P <.001), and a rapid decrease of high basal values of XIIa and F1.2 in 30 and 120 minutes, respectively. CONCLUSIONS: These data show a role of C1-INH in the control of platelet activity and that its deficiency increases platelet aggregability and plasma levels of XIIa and F1.2 in patients with HAE.

Adenosine Diphosphate↗

Laryngeal edema and death from asphyxiation after tooth extraction in four patients with hereditary angioedema.

BACKGROUND: Recurrent angioedema is the hallmark of various inherited or acquired angioedema diseases. Hereditary angioedema, or HAE, due to C1 inhibitor, or C1NH, deficiency has considerable implications for dental health care providers because dental surgery may trigger distressing and even life-threatening episodes. CASE DESCRIPTION: The authors reviewed the literature, focusing on the pathogenesis, clinical signs and treatment of HAE. They also provided case reports of four patients who died from laryngeal edema induced by tooth extraction. In patients with HAE, dental surgery--including tooth extraction--may be followed by self-limiting edema episodes, including lip swelling, facial swelling, tongue edema and laryngeal edema with upper airway obstruction. Preoperative prophylaxis has been performed with attenuated androgens, fresh frozen plasma, C1NH concentrate and antifibrinolytics. The four patients described underwent tooth extraction, which, after a symptom-free latency of four to 30 hours, provoked laryngeal edema. Three of the patients died of asphyxiation the night after surgery, and the fourth died on the second night. In three of the patients, laryngeal edema had not occurred previously. CLINICAL IMPLICATIONS: Before undergoing dental surgery, patients with a history of recurrent angioedema should be evaluated for C1NH deficiency. If it is present, they are at risk of developing life-threatening laryngeal edema.

Adult↗

Hereditary angioedema: new findings concerning symptoms, affected organs, and course.

PURPOSE: Hereditary angioedema (HAE) due to C1 inhibitor deficiency is clinically characterized by relapsing skin swellings, abdominal pain attacks, and life-threatening upper airway obstruction. Our aim was to examine a temporal and spatial pattern of the edema episodes by evaluating the long-term course of hereditary angioedema in order to establish a specific swelling pattern. SUBJECTS AND METHODS: Data were generated from 221 patients with C1 inhibitor deficiency by asking them about symptoms they experienced during their edema episodes. Documentation was accomplished through the use of standardized questionnaires. RESULTS: A total of 131110 edema episodes were observed. Clinical symptoms started at a mean age of 11.2 (SD 7.7) years. During the following cumulative 5736 years, only 370 (6.5%) symptom-free years occurred. Skin swellings, including extremity, facial, genital, and trunk swellings, and abdominal attacks occurred in 97.4% of all edema episodes of the disease. The other episodes were laryngeal edema (0.9%); edema of the soft palate (0.6%); tongue swellings (0.3%); headache episodes (0.7%); episodes affecting urinary bladder (0.3%), chest (0.2%), muscles (0.4%), joints (0.1%), kidneys (0.1%), and esophagus (0.05%), and were partly combined with other edema episodes. The per-patient analysis and the per-episode analysis revealed markedly discrepant results. On average, women had a more severe course of the disease than men. Patients with early onset of clinical symptoms were affected more severely than those with late onset. CONCLUSION: The described swelling pattern is specific for HAE and allows a tentative diagnosis based on clinical symptoms and the course of the disease.

Adolescent↗

Pharmacokinetics of C1-inhibitor protein in patients with acute myocardial infarction.

OBJECTIVES: C1-inhibitor protein (C1-INH) purified from pooled human plasma is used for the treatment of patients with hereditary angioedema. Recently, the beneficial effects of high-dose C1-INH treatment on myocardial ischemia or reperfusion injury have been reported in various animal models and in humans. We investigated the pharmacokinetic behavior of C1-INH in patients with acute myocardial infarction to calculate the amount of C1-INH required for optimal efficacy. METHODS: Twenty-two patients received an intravenous loading dose, followed by 48 hours of continuous infusion of C1-INH. Changes in the endogenous production of C1-INH were evaluated in 16 control patients with acute myocardial infarction. A 2-compartment model was used to estimate the fractional catabolic rate constant (FCR), transcapillary escape rate constant (TER), and extravascular return rate constant (ERR) of C1-INH. Software designed to analyze and fit measured data to unknown parameters in a system of differential equations was used to fit the experimental data against the 3-parameter model. RESULTS: With fixed TER and ERR values (0.014 h(-1) and 0.018 h(-1), respectively), 20 of the 22 cases yielded well-determined FCR values, and simultaneous fitting resulted in a median FCR of 0.011 h(-1) (95% confidence interval, 0.010 to 0.012 h(-1)) versus 0.025 h(-1) as reported in healthy control patients. Simultaneous estimation of TER, ERR, and FCR demonstrated weakly defined TER and ERR values, whereas the median FCR value remained unchanged. The use of a 2-compartment model resulted in a significantly better fit compared with the 1-compartment model. Physiologic explanations are offered for discrepancies in the literature. CONCLUSIONS: Dose calculation of C1-INH in patients treated with massive doses of C1-INH requires turnover parameters that differ from those found in healthy subjects, possibly because of suppression of continuous C1-INH consumption by target proteases.

Adult↗

Rapid detection by fluorescent multiplex PCR of exon deletions and duplications in the C1 inhibitor gene of hereditary angioedema patients.

Hereditary angioedema (HAE) is due to a variety of defects in the C1 inhibitor gene (C1NH gene), including approximately 20% of partial deletions/duplications whose boundaries are usually within Alu repeats. To ensure complete molecular characterization of C1 inhibitor deficiencies a fluorescent multiplex assay was constructed to amplify simultaneously five exons of C1NH and an exon of the BRCA1 gene. PCR protocols were optimized for these amplicons (size range between 300 and 700 bp). Forward and reverse chimeric primers that carry strand-specific 5' tags of 16 nucleotides were used to ensure similar levels of PCR products for each amplicon in the multiplex. Data were analyzed by superposing fluorescent profiles of test and control DNA and by visually comparing the normalized peak levels of corresponding amplicons, rather than by calculating the ratios of peak areas. Tests on a collection of known defects, including five different Alu-mediated deletions and a partial duplication have validated this approach. In a study of 19 sporadic cases of HAE, of which four had failed to reveal mutations upon screening all exons by fluorescent chemical cleavage, three de novo deletions were diagnosed by using this multiplex PCR approach: a deletion of exon 4, a deletion of exons 5 and 6, and an apparently complete gene deletion. Besides being suitable for the initial DNA screening of the C1NH gene in HAE patients prior to screening for point mutations, this method can be easily adapted to complex genes for the screening of rearrangements.

Angioedema↗

Hereditary angioedema: the mutation spectrum of SERPING1/C1NH in a large Spanish cohort.

Hereditary angioedema (HAE) is a disease caused by defects in the C1 inhibitor gene (SERPING1/C1NH). We screened the entire C1NH gene for mutations in a large series of 87 Spanish families (77 with type I, and 10 with type II HAE) by SSCP, sequencing, Southern blotting, and quantitative multiplex PCR of short fluorescent fragments (QMPSF), and we characterized several defects at the mRNA level. We found large rearrangements in 13 families, and point mutations or microdeletions/insertions in 74 families. The 13 large rearrangements included nine exon deletions, of which at least eight were distinct, two were distinct exon duplications, and two were rearrangements whose precise nature could not be determined. We confirmed that exon 4 is particularly prone to rearrangements. Thirty-six mutations were unreported, and included 10 microdeletions/insertions, 10 missense, five nonsense, eight splicing, and three splicing or missense mutations. Moreover, we detected six novel uncharacterized sequence variants (USV). RT-PCR studies showed that in addition to several intronic splice site mutations tested, the exonic mutations c.882C>G and c.884T>G, located near the 3' end of exon 5, also produced exon skipping. This is the first evidence of SERPING1/C1NH mutations in coding regions that differ from the canonical splice sites that affect splicing, which suggests the presence of an exonic splicing enhancer (ESE) in exon 5.

Alternative Splicing↗

C1 inhibitor gene sequence facilitates frameshift mutations.

Mutations disrupting the function or production of C1 inhibitor cause the disease hereditary angioneurotic edema. Patient mutations identified an imperfect inverted repeat sequence that was postulated to play a mechanistic role in the mutations. To test this hypothesis, the inverted repeat was cloned into the chloramphenicol acetyltransferase gene in pBR325 and its mutation rate was studied in four bacterial strains. These strains were selected to assay the effects of recombination and superhelical tension on mutation frequency. Mutations that revert bacteria to chloramphenicol resistance (Cmr) were scored. Both pairs of isogenic strains had reversion frequencies of approximately 10(-8). These rare reversion events in bacteria were most often a frameshift that involved the imperfect inverted repeat with a deletion or a tandem duplication, an event very similar to the human mutations. Increased DNA superhelical tension, which would be expected to enhance cruciform extrusion, did not accentuate mutagenesis. This finding suggests that the imperfect inverted repeat may form a stem-loop structure in the single-stranded DNA created by the duplex DNA melting prior to replication. Models explaining the slippage can be drawn using the lagging strand of the replication fork. In this model, the formation of a stem-loop structure is responsible for bringing the end of the deletion or duplication into close proximity.

Angioedema↗

The functional integrity of the serpin domain of C1-inhibitor depends on the unique N-terminal domain, as revealed by a pathological mutant.

C1-inhibitor (C1-Inh) is a serine protease inhibitor (serpin) with a unique, non-conserved N-terminal domain of unknown function. Genetic deficiency of C1-Inh causes hereditary angioedema. A novel type of mutation (Delta 3) in exon 3 of the C1-Inh gene, resulting in deletion of Asp62-Thr116 in this unique domain, was encountered in a hereditary angioedema pedigree. Because the domain is supposedly not essential for inhibitory activity, the unexpected loss-of-function of this deletion mutant was further investigated. The Delta 3 mutant and three additional mutants starting at Pro76, Gly98, and Ser115, lacking increasing parts of the N-terminal domain, were produced recombinantly. C1-Inh76 and C1-Inh98 retained normal conformation and interaction kinetics with target proteases. In contrast, C1-Inh115 and Delta 3, which both lack the connection between the serpin and the non-serpin domain via two disulfide bridges, were completely non-functional because of a complex-like and multimeric conformation, as demonstrated by several criteria. The Delta 3 mutant also circulated in multimeric form in plasma from affected family members. The C1-Inh mutant reported here is unique in that deletion of an entire amino acid stretch from a domain not shared by other serpins leads to a loss-of-function. The deletion in the unique N-terminal domain results in a "multimerization phenotype" of C1-Inh, because of diminished stability of the central beta-sheet. This phenotype, as well as the location of the disulfide bridges between the serpin and the non-serpin domain of C1-Inh, suggests that the function of the N-terminal region may be similar to one of the effects of heparin in antithrombin III, maintenance of the metastable serpin conformation.

Amino Acid Sequence↗

Symptoms, course, and complications of abdominal attacks in hereditary angioedema due to C1 inhibitor deficiency.

OBJECTIVES: Recurrent abdominal attacks belong to the cardinal and most distressing symptoms of hereditary angioedema (HAE) due to C1 inhibitor deficiency. They are characterized by crampy pain, but may include vomiting, diarrhea, and other features. Detailed clinical data about the symptoms and course of abdominal attacks have not been reported. METHODS: We retrospectively observed a total of 33,671 abdominal attacks in 153 patients with HAE including a prospectively examined subgroup of 23 patients. Symptoms, course, frequency of attacks, and complications were analyzed. RESULTS: The relation of mild, moderate, and severe attacks was 1:1.4:5.6 in the prospective part of the study. Extra-abdominal symptoms preceded the abdominal symptoms. The mean maximal pain score was 8.4 (range 1-10). Vomiting occurred in 73% (24,696) and diarrhea in 41% (13,682) of the attacks. Circulatory collapse accompanied 4.4% (1,468) of the attacks, with loss of consciousness (LOC) occurring in 2.2% (739). Nine patients could clearly distinguish two types of abdominal attacks: vomiting and diarrhea. Rare complications included tetany, hemorrhagic stools, and intussusception of the colon. In 28% (43) of the patients, recurrent abdominal attacks had started before the characteristic swelling of the skin had ever occurred. A model is proposed to classify the severity of the attacks and to describe the clinical course. CONCLUSIONS: Abdominal attacks in HAE constitute a more disabling and complex syndrome than previously assumed. Our results add to the understanding of symptoms and course of HAE and may aid in the early recognition of an impending attack and improve clinical management.

Abdominal Pain↗

Hereditary and acquired angioedema: problems and progress: proceedings of the third C1 esterase inhibitor deficiency workshop and beyond.

Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of facial, laryngeal, genital, or peripheral swelling or abdominal pain secondary to intra-abdominal edema. Resulting from mutations affecting C1 esterase inhibitor (C1-INH), inhibitor of the first complement system component, attacks are not histamine-mediated and do not respond to antihistamines or corticosteroids. Low awareness and resemblance to other disorders often delay diagnosis; despite availability of C1-INH replacement in some countries, no approved, safe acute attack therapy exists in the United States. The biennial C1 Esterase Inhibitor Deficiency Workshops resulted from a European initiative for better knowledge and treatment of HAE and related diseases. This supplement contains work presented at the third workshop and expanded content toward a definitive picture of angioedema in the absence of allergy. Most notably, it includes cumulative genetic investigations; multinational laboratory diagnosis recommendations; current pathogenesis hypotheses; suggested prophylaxis and acute attack treatment, including home treatment; future treatment options; and analysis of patient subpopulations, including pediatric patients and patients whose angioedema worsened during pregnancy or hormone administration. Causes and management of acquired angioedema and a new type of angioedema with normal C1-INH are also discussed. Collaborative patient and physician efforts, crucial in rare diseases, are emphasized. This supplement seeks to raise awareness and aid diagnosis of HAE, optimize treatment for all patients, and provide a platform for further research in this rare, partially understood disorder.

Angioedema↗