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Background: The generic 36-item Short-Form Health Survey (SF-36v2) has been used to assess health related quality of life in adult patients with hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) even though it has not yet been validated for use in this specific disease.Objective: This study aims to validate the SF-36v2 for use in adult patients with C1-INH-HAE.Results: There was a very low item non-response rate (1-3.4%), with a high ceiling effect in 25/35 items and a low floor effect in 3/35 items. A moderate ceiling effect was observed in 5/8 dimensions of the SF-36v2, whereas no floor effect was noticed in any of the dimensions. Internal consistency was good to excellent with Cronbach's alpha coefficient ranging between 0.82 and 0.93 for the different dimensions. Construct validity was good: seven out of the 8 hypotheses defined on clinical criteria were confirmed, discriminant validity assessment showed significant differences among patients with different C1-INH-HAE severity, convergent validity showed a good correlation among the physical and mental component summaries of the SF-36v2 and the HAE-QoL total score (0.45 and 0.64 respectively, P < 0.001). Test-retest reliability was high with intraclass correlation coefficient varying from 0.758 to 0.962. The minimal clinically important difference was calculated by distribution methods and small differences in the domain scores and in the component summaries scores were shown to be meaningful.  CONCLUSIONS: The psychometric properties of the SF-36v2 show it can be a useful tool to assess HRQoL in adult patients with C1-INH-HAE, although with some content validity limitation.Methods: The psychometric properties of the SF-36v2 were evaluated in an international setting based on responses from 290 adult C1-INH-HAE patients in 11 countries. [ABSTRACT FROM AUTHOR]

Introduction. We shall present a case of a two-month old infant who has developed a haemolytic uremic syndrome as an atypical complication of Bordetella pertussis infection. The observation that the development of haemolytic uremic syndrome is a late complication of Bordetella pertussis infection may be a clue for further studies. Case outline. A two-month-old female infant was admitted to the hospital because of fever, intensive cough, shortness of breath and poor feeding. Real-time polymerase chain reaction (PCR) for Bordetella pertussis was positive. A macrolide was introduced in therapy. On the eighth hospital day, the infant’s condition improved, she became afebrile and eupneic. On the 16th hospital day, she developed signs of progressive respiratory distress and oliguric acute kidney injury. Hemolytic uremic syndrome (HUS) was diagnosed, so the therapy with the fresh frozen plasma (FFP) transfusion, therapeutic plasma exchange and peritoneal dialysis was initiated. Levels of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) were decreased, while the levels of factor H, factor B, and factor I were normal. Despite the full supportive and targeted care, severe multiple organ failure had developed and on the 24th hospital day the infant died. Conclusion. Further studies are necessary to identify the mechanism of potential interaction between pertussis toxins, pathophysiology of the infection and the interaction of complement activation, coagulation and the regulation of these cascades.

Danazol is a drug most widely used for the prophylaxis of hereditary angioedema resulting from the deficiency of the C1-inhibitor. Potential hepatotoxic or liver tumor-inducing side effects of long-term danazol prophylaxis have been investigated during the follow-up of hereditary angioedema patients. Characteristic parameters of liver function (including bilirubin, GOT, GPT, [gamma]GT, total protein, ALP, LDH), as well as findings of viral serology screens and abdominal ultrasonography-determined during years 0 and 5 of follow-up of patient groups taking/not taking danazol-have been reviewed and analyzed comparatively. From a population of 126 hereditary angioedema patients, 46 subjects taking danazol and another 46 not taking danazol fulfilled the inclusion criteria. Longitudinal follow-up did not reveal any clinically relevant difference between the liver function parameters determined in years 0 and 5 in the two groups. Abdominal ultrasound did not detect neoplastic or other potentially treatment-related alterations of the liver parenchyma. There were no discontinuations of treatment during the study. Our results clearly suggest that, administered at the lowest effective dose, danazol does not induce liver injury in hereditary angioedema patients. [ABSTRACT FROM AUTHOR]

Background: Clinical trials investigating drugs for the acute treatment of hereditary angioedema attacks have assessed many different outcomes. This heterogeneity limits the comparability of trial results and may lead to selective outcome reporting bias and a high burden on trial participants., Objective: To achieve consensus on a core outcome set composed of key outcomes that ideally should be used in all clinical efficacy trials involving the acute treatment of hereditary angioedema attacks., Methods: We conducted a Delphi consensus study involving all relevant parties: patients with hereditary angioedema, hereditary angioedema expert clinicians and clinical researchers, pharmaceutical companies, and regulatory bodies. Two Internet-based survey rounds were conducted. In round 1, panelists indicated the importance of individual outcomes used in clinical trials on a 9-point Likert scale. Based on these results, a core outcome set was developed and voted on by panelists in round 2., Results: A total of 58 worldwide panelists completed both rounds. The first round demonstrated high importance scores and substantial agreement among the panelists. In the second round, a consensus of 90% or greater was achieved on a core outcome set consisting of five key outcomes: change in overall symptom severity at one predetermined time point between 15 minutes and 4 hours after treatment, time to end of progression of all symptoms, the need for rescue medication during the entire attack, impairment of daily activities, and treatment satisfaction., Conclusions: This international study obtained a high level of consensus on a core outcome set for the acute treatment of hereditary angioedema attacks, consisting of five key outcomes., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Although a number of high-risk breast cancer genes have been identified, including BRCA1 and BRCA2 , the risk profile of many high-risk families cannot be explained using known breast cancer genes. Previously, we have shown strong indications of new breast cancer risk loci at chromosomes 2p, 6q, and 14q in a family of six generations including 10 breast cancer cases. In this study, we identified and traced four new family branches descending from siblings of the parents in the top generation of the studied family. One distantly related branch included four breast cancer cases, two of whom were diagnosed at age < 45 years. DNA samples from the cases were typed at selected polymorphic markers from all three chromosome loci, to test identical origin of the haplotypes. All four cases were shown to segregate a common 6q haplotype with a region identical to the previously identified 6q haplotype. The data strongly support a new breast cancer locus at 6q, and narrow it down to a 17 MB interval at 6q15-q21.

Background: Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is a rare disease caused by low level (type I) or dysfunction (type II) of the C1-inhibitor protein with subsequent reduction of certain complement protein levels., Methods: To develop and test the reliability of a two-tier method based on C1-INH and C4 quantitation followed by genetic analysis from dried blood spot (DBS) for establishing the diagnosis of C1-INH-HAE. C1-INH and C4 proteins have been quantified in human plasma using a classical immuno-assay and in DBS using a newly developed proteolytic liquid chromatography-mass spectrometry method. Genetic analysis was carried out as reported previously (PMID: 35386643) and by a targeted next-generation sequencing panel, multiplex ligation-dependent probe amplification and in some cases whole genome sequencing., Results: DBS quantification of C1-INH and C4 showed the same pattern as plasma, offering the possibility of screening patients with AE symptoms either locally or remotely. Genetic analysis from DBS verified each of the previously identified SERPING1 mutations of the tested C1-INH-HAE patients and revealed the presence of other rare variations in genes that may be involved in the pathogenesis of AE episodes., Conclusions: C1-INH/C4 quantification in DBS can be used for screening of hereditary AE and DNA extracted from dried blood spots is suitable for identifying various types of mutations of the SERPING1 gene., (© 2023 The Authors. Clinical and Translational Allergy published by John Wiley & Sons Ltd on behalf of European Academy of Allergy and Clinical Immunology.)

Rationale & Objective: Pregnancy, delivery, and neonatal outcomes in women with complement-mediated thrombotic microangiopathy (cTMA) have not been well described. A better understanding of these outcomes is necessary to provide women with competent pregnancy counseling., Study Design: Cohort study., Setting and Participants: Women with a history of cTMA and pregnancies enrolled into the Vienna thrombotic microangiopathy cohort., Exposure: New onset or relapses of cTMA., Outcomes: Pregnancy, delivery, and neonatal outcomes of pregnancies in women (a) before cTMA manifestation, (b) complicated by pregnancy-associated cTMA (P-cTMA), and (c) after first manifestation of cTMA or P-cTMA., Analytical Approach: Mixed models were used to adjust the comparison of pregnancy, delivery, and neonatal outcomes between conditions (before, with, and after cTMA) for repeated pregnancies using the mother's ID as random factor. In addition, the fixed factors, mother's age and neonate's sex, were used for adjustment. For (sex-adjusted and age-adjusted) centile outcomes, only the mother's age was used. Adjusted odds ratios were derived from a generalized linear mixed model with live birth as the outcome. Least squares means and pairwise differences between them were derived from the linear mixed models for the remaining outcomes., Results: 28 women reported 74 pregnancies. Despite higher rates of fetal loss before the diagnosis of P-cTMA and preterm births with P-cTMA, most of the women were able to conceive successfully. Neonatal development in all 3 conditions of pregnancies was excellent. Pregnancy and neonatal outcomes were better in women with a pregnancy after the diagnosis of cTMA., Limitations: Although our data set comprises a considerable number of 74 pregnancies, the effective sample size is lower because only 28 mothers with multiple pregnancies were observed. The statistical power for detecting clinically relevant effects was probably low. A recall bias for miscarriages cannot be ruled out., Conclusions: Prepregnancy counseling of women with a history of cTMA can be supportive of their desire to become pregnant., (© 2023 The Authors.)

Introduction: While complement is a contributor to disease severity in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, all three complement pathways might be activated by the virus. Lectin pathway activation occurs through different pattern recognition molecules, including mannan binding lectin (MBL), a protein shown to interact with SARS-CoV-2 proteins. However, the exact role of lectin pathway activation and its key pattern recognition molecule MBL in COVID-19 is still not fully understood., Methods: We therefore investigated activation of the lectin pathway in two independent cohorts of SARS-CoV-2 infected patients, while also analysing MBL protein levels and potential effects of the six major single nucleotide polymorphisms (SNPs) found in the MBL2 gene on COVID-19 severity and outcome., Results: We show that the lectin pathway is activated in acute COVID-19, indicated by the correlation between complement activation product levels of the MASP-1/C1-INH complex (p=0.0011) and C4d (p<0.0001) and COVID-19 severity. Despite this, genetic variations in MBL2 are not associated with susceptibility to SARS-CoV-2 infection or disease outcomes such as mortality and the development of Long COVID., Conclusion: In conclusion, activation of the MBL-LP only plays a minor role in COVID-19 pathogenesis, since no clinically meaningful, consistent associations with disease outcomes were noted., Competing Interests: Author ET is an employee of Hycult Biotech. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hurler, Szilágyi, Mescia, Bergamaschi, Mező, Sinkovits, Réti, Müller, Iványi, Gál, Gopcsa, Reményi, Szathmáry, Lakatos, Szlávik, Bobek, Prohászka, Förhécz, Csuka, Kajdácsi, Cervenak, Kiszel, Masszi, Vályi-Nagy, Würzner, Cambridge Institute of Therapeutic Immunology and Infectious Disease-National Institute of Health Research (CITIID-NIHR) COVID BioResource Collaboration, Lyons, Toonen and Prohászka.)

Atypical hemolytic uremic syndrome (aHUS), also called complement-mediated hemolytic uremic syndrome (CM-HUS), is a rare disease caused by dysregulation in the alternative complement activation pathway. It is a life-threatening condition causing ischemia of a number of organs, and it typically causes acute kidney injury. This disorder may be triggered by various factors including viral or bacterial infections, pregnancy, surgery, and injuries. In about 60% of cases, the genetic origin of the disease can be identified-commonly mutations affecting complementary factor H and MCP protein. Eculizumab, a monoclonal antibody to the C5 component of the complement, represents the current effective treatment.We describe a case of a young woman with a previous history of polyvalent allergies, who developed atypical hemolytic uremic syndrome after vaccination with mRNA vaccine against SARS-CoV-2. The disease manifested by scleral bleeding, acute renal insufficiency, anemia, and thrombocytopenia. The patient was treated with plasma exchanges without sufficient effect; remission occurred only after starting treatment with eculizumab. Genetic examination showed that the patient is a carrier of multiple inherited risk factors (a rare pathogenic variant in CFH , MCPggaac haplotype of the CD46 gene, and the risk haplotype CFH H3). The patient is currently in hematological remission with persistent mild renal insufficiency, continuing treatment with eculizumab/ravulizumab. By this case report, we meant to point out the need for careful monitoring of people after vaccination, as it may trigger immune-mediated diseases, especially in those with predisposing factors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rysava, Peiskerova, Tesar, Benes, Kment, Szilágyi, Csuka and Prohászka.)

De novo thrombotic microangiopathy (TMA) is associated with poor kidney graft survival, and as we previously described, it is a recipient driven process with suspected genetic background. Direct Sanger sequencing was performed in 90 KTR with de novo TMA and 90 corresponding donors on selected regions in CFH, CD46, C3 , and CFB genes that involve variations with a functional effect or confer a risk for aHUS. Additionally, 37 recipients of paired kidneys who did not develop TMA were analyzed for the MCPggaac haplotype. Three-years death-censored graft survival was assessed using Kaplan-Meier and Cox regression models. The distribution of haplotypes in all groups was in the Hardy-Weinberg equilibrium and there was no clustering of haplotypes in any group. In the TMA group, we found that MCPggaac haplotype carriers were at a significantly higher risk of graft loss compared to individuals with the wild-type genotype. Worse 3-year death-censored graft survival was associated with longer cold ischemia time (HR 1.20, 95% CI 1.06, 1.36) and recipients' MCPggaac haplotype (HR 3.83, 95% CI 1.42, 10.4) in the multivariable Cox regression model. There was no association between donor haplotypes and kidney graft survival. Similarly, there was no effect of the MCPggaac haplotype on 3-year graft survival in recipients of paired kidneys without de novo TMA. Kidney transplant recipients carrying the MCPggaac haplotype with de novo TMA are at an increased risk of premature graft loss. These patients might benefit from therapeutic strategies based on complement inhibition., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Petr, Csuka, Hruba, Szilágyi, Kollar, Slavcev, Prohászka and Viklicky.)

Here, we present the findings of an investigation involving two male siblings with juvenile total tooth loss, early-onset chronic leg ulcers, and autoimmune thyroiditis, as well as focal segmental glomerulosclerosis with associated pulmonary emphysema in one and diabetes mellitus in the other. The clinical picture and lupus anticoagulant, cryoglobulin, and cold agglutinin positivity suggested the diagnosis of antiphospholipid syndrome. Flow cytometry analysis showed immunophenotypes consistent with immune dysregulation: a low number of naive T cells, elevated CD4 + T cell counts, and decreased CD8 + T-cell counts were detected, and more than half of the T-helper population was activated. Considering the siblings' almost identical clinical phenotype, the genetic alteration was suspected in the background of the immunodeficiency. Whole exome sequencing identified a previously not described hemizygous nonsense variant (c.650G>A, p.W217X) within exon 6 of the moesin ( MSN ) gene localized on chromosome X, resulting in significantly decreased MSN mRNA expression compared to healthy controls. We present a putative new autoimmune phenotype of Immunodeficiency 50 (MIM300988) characterized by antiphospholipid syndrome, Hashimoto's thyroiditis, leg ulcers, and juvenile tooth loss, associated with W217X mutation of the MSN gene., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kovács, Kárteszi, Prohászka, Kalmár, Késmárky, Koltai, Nagy, Sebők, Vas, Molnár, Berki, Böröcz, Gyömörei, Szalma, Egyed, Horváth, Oláh, Csuka, Németh and Gyulai.)

Existing evidence indicates that modifier genes could change the phenotypic outcome of the causal SERPING1 variant and thus explain the expression variability of hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE). To further examine this hypothesis, we investigated the presence or absence of 18 functional variants of genes encoding proteins involved in the metabolism and function of bradykinin, the main mediator of C1-INH-HAE attacks, in relation to three distinct phenotypic traits of patients with C1-INH-HAE, i.e., the age at disease onset, the need for long-term prophylaxis (LTP), and the severity of the disease. Genetic analyses were performed by a validated next-generation sequencing platform. In total, 233 patients with C1-INH-HAE from 144 unrelated families from five European countries were enrolled in the study. Already described correlations between five common functional variants [ F12 -rs1801020, KLKB1 -rs3733402, CPN1 -rs61751507, and two in SERPING1 (rs4926 and rs28362944)] and C1-INH-HAE severity were confirmed. Furthermore, significant correlations were found between either the age at disease onset, the LTP, or the severity score of the disease and a series of other functional variants ( F13B -rs6003, PLAU -rs2227564, SERPINA1 -rs28929474, SERPINA1 -rs17580, KLK1 -rs5515, SERPINE1 -rs6092, and F2 -rs1799963). Interestingly, correlations uncovered in the entire cohort of patients were different from those discovered in the cohort of patients carrying missense causal SERPING1 variants. Our findings indicate that variants other than the SERPING1 causal variants act as independent modifiers of C1-INH-HAE severity and could be tested as possible prognostic biomarkers., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Parsopoulou, Loules, Zamanakou, Csuka, Szilagyi, Kompoti, Porebski, Psarros, Magerl, Valerieva, Staevska, Obtulowicz, Maurer, Speletas, Farkas and Germenis.)

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast-feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients., (© 2022 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Complement deficiencies have been considered to be rare for many decades, but this assumption is changing year by year. Recognition of these conditions significantly increases thanks to the availability of different testing approaches and due to clinical awareness. Furthermore, sequencing technologies (including Sanger sequencing, targeted gene panels, and whole exome/genome sequencing) may facilitate the identification of the underlying disease-causing genetic background. On the other hand, functional characterization of the identified possibly pathogenic variations and performing family studies, as illustrated by some of our cases, remain similarly important to establish a precise clinical diagnosis facilitating the most appropriate management. Here, we present 4 illustrative cases with complement deficiencies of diverse etiologies and also provide an educative, step-by-step description on how to identify the underlying cause of complement deficiency based on the results of complement laboratory testing., (Copyright © 2022 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Hereditary Angioedema with C1-inhibitor deficiency (C1-INH-HAE) is a rare disease characterized by recurrent subcutaneous and/or submucosal edematous (HAE) episodes, which may occur at any age. The mean age of the symptom onset is 10-12 years. Diagnostic protocols differ by age group and family history., Methods: We retrospectively analyzed clinical and laboratory data (C4-, C1-INH concentration and function) from 49 pediatric patients diagnosed with C1-INH deficiency at our Angioedema Center between 2001 and 2020. Moreover, we analyzed the connection between complement parameters and symptom onset., Results: From the 49 pediatric patients [boy/girl: 23/26, the average age of diagnosis: 6.7 years (min: 0-max: 18.84)], the majority (36/49, 73%) was diagnosed as the result of family screening. Of all the enrolled patients, 34% (17/49) experienced symptoms before the diagnosis. During the observational period, 33% (16/49) of the patients remained asymptomatic, while 33% (16/49) became symptomatic. The average age at symptom onset was 7.8 years (min: 0.5-max: 18). Only 27% (13/49) of pediatric patients were diagnosed after referrals to our center because of typical symptoms. From those patients diagnosed with family screening, 4/36 experienced symptoms at or before the time of the diagnosis. In the case of five newborns from the family screening group, umbilical cord blood samples were used for complement testing. In the case of 3/36 patients, the first complement parameters did not clearly support the disease, but the presence of the mutation identified in the family verified the diagnosis. Complement results were available from 11 patients who became symptomatic during the observational period. Complement parameters 1 year prior to and after the onset of symptoms were compared, and significantly lower concentrations of C1-INH ( p = 0.0078) were detected after the onset of symptoms compared to the preceding (symptom-free) period., Discussion: The majority of pediatric patients were diagnosed as a result of family screening before the onset of symptoms. Early diagnosis allows supplying the patients with special acute treatment for HAE attacks, which may occur at any time. Our results highlight the importance of DNA analysis in pediatric patients in case of a known mutation in the family, and an ambiguous result of complement testing., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Andrási, Balla, Visy, Szilágyi, Csuka, Varga and Farkas.)

Background: Dysregulation of complement system is thought to be a major player in development of multi-organ damage and adverse outcomes in patients with coronavirus disease 2019 (COVID-19). This study aimed to examine associations between complement system activity and development of severe acute kidney injury (AKI) among hospitalized COVID-19 patients., Materials and Methods: In this multicenter, international study, complement as well as inflammatory and thrombotic parameters were analyzed in COVID-19 patients requiring hospitalization at one US and two Hungarian centers. The primary endpoint was development of severe AKI defined by KDIGO stage 2+3 criteria, while the secondary endpoint was need for renal replacement therapy (RRT). Complement markers with significant associations with endpoints were then correlated with a panel of inflammatory and thrombotic biomarkers and assessed for independent association with outcome measures using logistic regression., Results: A total of 131 hospitalized COVID-19 patients (median age 66 [IQR, 54-75] years; 54.2% males) were enrolled, 33 from the US, and 98 from Hungary. There was a greater prevalence of complement over-activation and consumption in those who developed severe AKI and need for RRT during hospitalization. C3a/C3 ratio was increased in groups developing severe AKI (3.29 vs. 1.71; p < 0.001) and requiring RRT (3.42 vs. 1.79; p < 0.001) in each cohort. Decrease in alternative and classical pathway activity, and consumption of C4 below reference range, as well as elevation of complement activation marker C3a above the normal was more common in patients progressing to severe AKI. In the Hungarian cohort, each standard deviation increase in C3a ( SD = 210.1) was independently associated with 89.7% increased odds of developing severe AKI (95% CI, 7.6-234.5%). Complement was extensively correlated with an array of inflammatory biomarkers and a prothrombotic state., Conclusion: Consumption and dysregulation of complement system is associated with development of severe AKI in COVID-19 patients and could represent a promising therapeutic target for reducing thrombotic microangiopathy in SARS-CoV-2 infection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Henry, Sinkovits, Szergyuk, de Oliveira, Lippi, Benoit, Favaloro, Pode-Shakked, Benoit, Cooper, Müller, Iványi, Gál, Réti, Gopcsa, Reményi, Szathmáry, Lakatos, Szlávik, Bobek, Prohászka, Förhécz, Csuka, Hurler, Kajdácsi, Cervenak, Mező, Kiszel, Masszi, Vályi-Nagy and Prohászka.)

Background: Hereditary angioedema (HAE) due to C1-inhibitor (C1-INH) deficiency (C1-INH-HAE) is a rare autosomal dominant disorder, characterized by recurrent, unpredictable edematous symptoms involving subcutaneous, and/or submucosal tissue. C1-INH-HAE may be caused by more than 700 different mutations in the gene encoding C1-INH ( SERPING1 ) that may lead to decreased protein synthesis or to functional deficiency., Methods: Concentrations of C1-INH, C4, C1q, and anti-C1-INH antibodies, as well as functional C1-INH activity were determined in subjects suffering from edematous symptoms and admitted to the Hungarian Angioedema Center of Reference and Excellence. In those patients, who were diagnosed with C1-INH-HAE based on the complement measurements, SERPING1 was screened by bidirectional sequencing following PCR amplification and multiplex ligation-dependent probe amplification. For detecting large deletions, long-range PCRs covering the entire SERPING1 gene by targeting 2-7 kb long regions were applied., Results: Altogether 197 individuals with C1-INH deficiency belonging to 68 families were identified. By applying Sanger sequencing or copy number determination of SERPING1 exons, 48 different mutations were detected in 66/68 families: 5 large and 15 small insertions/deletions/delins, 16 missense, 6 nonsense, and 6 intronic splice site mutations. Two novel variations (p.Tyr199Ser [c.596A>C] and the duplication of exon 7) were shown to cosegregate with deficient C1-inhibitor level and activity, while two other variations were detected in single patients (c.797&#95;800delinsCTTGGAGCTCAAGAACTTGGAGCT and c.812dup). A series of long PCRs was applied in the remaining 2 families without an identified mutation and a new, 2606 bp long deletion including the last 91 bp of exon 6 (c.939&#95;1029+2515del) was identified in all affected members of one pedigree. In the remaining one family, a deep intronic SERPING1 variation (c.1029+384A>G) was detected by a targeted next-generation sequencing panel as reported previously., Conclusions: Sequencing and copy number determination of SERPING1 exons uncover most pathogenic variants in C1-INH-HAE patients, and further methods are worth to be applied in cases with unrevealed genetic background. Since knowledge of the genetic background may support the establishment of the correct and early diagnosis of C1-INH-HAE, identification of causative mutations and reporting data supporting the interpretation on the pathogenicity of these variants is of utmost importance., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Szabó, Csuka, Andrási, Varga, Farkas and Szilágyi.)

BACKGROUND Adverse reaction to histamine found in food and beverages is still a debated entity. It presents with a diverse, multisystemic clinical picture and lacks objective diagnostic criteria. CASE REPORT We report a case of severe adverse reaction to histamine in food and beverages. The 36-year-old White man had diet-dependent problems for 17 years that involved periodic erythematous rash, fever, headaches, nausea, and upper respiratory symptoms. The symptoms developed in the same chronologic order each time. The course of the disease could be divided into a first (prodromal, gastrointestinal), a second (acute, dermal), and a third (subacute, respiratory) phase. The symptoms occurred every 3-6 weeks and lasted for 10-14 days. The differential diagnosis was time-consuming and very detailed. Family history, genetic testing, and oral histamine provocation testing supported the diagnosis of an adverse reaction to histamine in food and beverages. A low-histamine diet resulted in a symptom-free state. Follow-up lasted longer than 24 months. CONCLUSIONS This presentation of an adverse reaction to histamine in food and beverages can serve as a textbook example where a chronological, syndrome-like order of symptom appearance is described. To the best of our knowledge, this is the first report of a severe adverse reaction to histamine in food and beverages, where symptoms are described in 3 distinct recurring phases.