Clinical practice. Hereditary angioedema

Case Report: Identification of a novel mutation, c.1067T > A, in the SERPING1 gene in a Chinese male with type 1 hereditary angioedema

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disorder characterized by recurrent, unpredictable episodes of angioedema that commonly involve the face, limbs, respiratory tract, and gastrointestinal tract. Clinical presentations vary substantially among individuals, increasing the likelihood of misdiagnosis or missed diagnosis. In severe cases, if not properly managed, laryngeal edema can result in asphyxiation or even death. Here, we report a Chinese male patient who experienced recurrent limb swelling and abdominal pain. Laboratory tests revealed low levels of complement C4 and C1 inhibitors, along with impaired C1 inhibitor function. Genomic DNA extracted from peripheral blood samples underwent PCR amplification and Sanger sequencing, which identified a de novo heterozygous mutation in the SERPING1 gene at chr11:57379227, confirming a novel missense mutation NM_000062.c.1067T > A (p.V356E). Ultimately, the patient was diagnosed with HAE-C1INH-Type1 and successfully protected from recurrent attacks through subcutaneous administration of lanadelumab.

Prediction of hereditary angioedema during attacks in patients with recurrent angioedema: Awareness at a glance with the hereditary angioedema prediction score

BACKGROUND/AIM

Misdiagnosis of hereditary angioedema (HAE) leads to inappropriate management of the attacks. A scoring system that anticipates diagnosis can be beneficial for clinicians who are unfamiliar with angioedema. This study aims to develop a practical scoring system for use during acute attacks to predict HAE in patients with recurrent angioedema (RAE).

METHOD

To predict HAE, nine HAE experts unanimously identified five predictive items (PIs); absence of urticaria, presence of abdominal pain episodes, family history, early onset of attacks and previous unresponsiveness to anti-histaminergic treatments. The researchers questioned 106 patients with HAE and 155 patients with mast cell-mediated angioedema (MMAE) about PIs. A score was attributed to each significant PI based on OR values obtained through logistic regression analysis. The cut-off point for the prediction of HAE and its sensitivity and specificity were determined by ROC curve analysis.

RESULTS

In a univariate analysis, all items showed significant differences between HAE and MMAE patients. Regression analysis attributed scores as follows: 23 points for the absence of urticaria, 11 points for the abdominal pain episodes, 9 points for family history, and 53 points for unresponsiveness to antihistaminergic treatments. No score was attributed to early onset of age (p > 0.05). The ROC analysis revealed an area under the curve of 0.990, with a total score of ≥38 demonstrating the best sensitivity (96.4%) and specificity (96.1%).

CONCLUSIONS

HAEps is a valuable tool for diagnosing HAE in patients with RAE. A score of 38 or more indicates the possible presence of HAE with substantial sensitivity and specificity.

Safety and pharmacokinetics of long-acting plasma kallikrein inhibitor navenibart (STAR-0215) in healthy adults

BACKGROUND

Hereditary angioedema (HAE) is a rare, autosomal-dominant disorder characterized by bradykinin-mediated episodic, localized swelling that can be fatal. Currently approved long-term prophylactic therapies for HAE attacks incur substantial treatment burden through frequent dosing. Navenibart (STAR-0215) is a monoclonal antibody inhibitor of plasma kallikrein modified to extend circulating half-life and is under investigation for HAE prophylaxis.

OBJECTIVE

To evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of a single dose of navenibart in healthy adults and to assess the feasibility of every 3- and 6-month dosing.

METHODS

In this phase 1a study, participants were randomized 3:1 to receive placebo or navenibart in escalating (100-1200 mg) dosing cohorts. Safety outcomes, including treatment-emergent adverse events (TEAEs) and serious AEs, were monitored until the end of the study (day 224). Additional end points included pharmacokinetic parameters and inhibition of plasma kallikrein activity.

RESULTS

In total, 31 participants received navenibart and 10 received placebo. The median age of the participants was 36 years; 53.7% were male; 51.2% were Black or African American. Rates of TEAEs were similar between navenibart and placebo, and no serious AEs were reported. Navenibart-related TEAEs included injection site reactions, inclusive of erythema, pruritus, and swelling, which resolved without intervention. For all doses more than or equal to 300 mg, navenibart mean half-life ranged from 82 to 105 days and inhibition of factor XIIa-induced plasma kallikrein activity vs placebo was statistically significant (P < .05). Statistically significant inhibition of factor XIIa-induced plasma kallikrein activity vs placebo (P < .05) was observed with all doses of navenibart.

CONCLUSION

In this first-in-human study, up to 1200 mg of navenibart was well tolerated and demonstrated an extended half-life with durable plasma kallikrein inhibition.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05477160.

Comorbidities in Canadian patients with hereditary angioedema: a quantitative survey study

BACKGROUND

Evidence linking hereditary angioedema (HAE) to the potential association of developing other comorbidities, and how it is affected by HAE treatment is needed. The objective of this study is to identify comorbidities and measure the prevalence in HAE patients, compared to the prevalence in the general population using multiple Canadian sources when available.

METHODS

A quantitative survey design via a self-administered anonymous online questionnaire was conducted from October 13, 2022, to January 11, 2023. Respondents were individuals with HAE, enrolled in the CSL Behring patient support program (CSL Behring PLUS+; PSP).

RESULTS

This study included 123 patients (81% female; 60% HAE-1/HAE-2, 24% HAE Normal C1-INH (nC1-INH), 16% unsure of HAE type; 85% of patients were on long-term prophylaxis plus on-demand). Patients reported using the following HAE treatments: C1-esterase inhibitor (subcutaneous or intravenous), lanadelumab, icatibant, danazol, and tranexamic acid. Respondents (69%) reported at least one: autoimmune condition, asthma, or allergy. Reported autoimmune conditions (psoriasis, rheumatoid arthritis, inflammatory bowel disease, chronic urticaria, lupus, and psoriatic arthritis) were much higher than the general population (31% versus 5-8%). Patient-reported allergies were two times higher than the general population (54% versus 27%; i.e., aeroallergens) and asthma rates nearly two times higher than the general population (17% versus 8-11%).

CONCLUSION

This cohort of HAE patients, most of whom were on prophylaxis, reported an increased prevalence of certain comorbidities compared to the general Canadian population. Healthcare professionals should be aware of the potentially increased risk of autoimmune conditions, allergies, and asthma in patients with HAE.

A COSMIN systematic review of instruments for evaluating health-related quality of life in people with Hereditary Angioedema

BACKGROUND

Hereditary angioedema (HAE) adversely affects health-related quality of life (HRQoL). HAE often compromises the HRQoL due to the impact on functional capacity caused by edema, pain, other symptoms, and psychosocial factors. Patient-Reported Outcome Measures (PROMs) focus on HRQoL and are crucial tools for evaluating the burden of the disease and choosing the most appropriate interventions for this population. However, no comprehensive evaluations of the characteristics of the available measurements to assess HRQoL have been conducted for this population.

AIM

To identify, analyze, and summarize the PROMs assessing HRQoL in individuals with HAE-C1-INH, addressing the gap in standardized assessment tools.

METHODS

A systematic review was conducted up to December 2023 in PubMed, Scopus, Web of Science, Embase, and CINAHL databases, following PRISMA guidelines without language or time restrictions. Psychometric properties of the identified PROMs were appraised using COSMIN standards, and evidence was synthesized using a modified GRADE approach.

RESULTS

From seven studies, five HRQoL PROMs were identified: two generic (SF-36 and SF-36v2) and three disease-specific (HAE-QoL, HAEA-QoL, and AE-QoL). These PROMs generally lacked comprehensive content, structural and cross-cultural validation, with none meeting the criteria for measurement invariance. This limitation affects their applicability across different demographics and cultures. However, the HAE-QoL and AE-QoL instruments were recognized for having moderate quality evidence, suggesting their potential reliability and validity.

CONCLUSIONS

This systematic review provides a moderate recommendation for the use of HAE-QoL and AE-QoL in assessing HRQoL in adults with HAE. Despite identified gaps, the moderate evidence quality for these tools supports their use, pending further validation, involving younger age groups and disease-specific contents in the assessments. Developing culturally and demographically adaptable PROMs is, therefore, a priority to improve the accuracy of PROMs in this field.

REVIEW REGISTRATION NUMBER

PROSPERO registration number is CRD42023440137.

CRISPR-Based Therapy for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare genetic disease characterized by severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy that is based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1). A single dose of NTLA-2002 may provide lifelong control of angioedema attacks.

METHODS

In this phase 2 portion of a phase 1-2 trial, we randomly assigned adults with hereditary angioedema in a 2:2:1 ratio to receive NTLA-2002 in a single dose of 25 mg or 50 mg or placebo. The primary end point was the number of angioedema attacks per month (the monthly attack rate) from week 1 through week 16. Secondary end points included safety, pharmacokinetics, and pharmacodynamics (i.e., the change from baseline in total plasma kallikrein protein level); exploratory end points included patient-reported outcomes.

RESULTS

Of the 27 patients who underwent randomization, 10 received 25 mg of NTLA-2002, 11 received 50 mg, and 6 received placebo. From week 1 through week 16, the estimated mean monthly attack rate was 0.70 (95% confidence interval [CI], 0.25 to 1.98) with 25 mg of NTLA-2002, 0.65 (95% CI, 0.24 to 1.76) with 50 mg, and 2.82 (95% CI, 0.80 to 9.89) with placebo; the difference in the estimated mean attack rate with NTLA-2002 as compared with placebo was -75% with 25 mg and -77% with 50 mg. Among patients who received NTLA-2002, 4 of the 10 patients who received 25 mg (40%) and 8 of the 11 who received 50 mg (73%) were attack-free with no additional treatment during the period from week 1 through week 16. The most common adverse events among patients who received NTLA-2002 were headache, fatigue, and nasopharyngitis. The mean percent change in total plasma kallikrein protein levels from baseline to week 16 was -55% with 25 mg and -86% with 50 mg; levels remained unchanged with placebo.

CONCLUSIONS

NTLA-2002 administered in a single dose of 25 mg or 50 mg reduced angioedema attacks and led to robust and sustained reduction in total plasma kallikrein levels in patients with hereditary angioedema. These results support continued investigation in a larger phase 3 trial. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830; EudraCT number, 2021-001693-33.).

N-glycosylation in the SERPIN domain of the C1-esterase inhibitor in hereditary angioedema

Hereditary angioedema is an autosomal dominant disorder caused by defects in C1-esterase inhibitor (C1-INH), resulting in poorly controlled activation of the kallikrein-kinin system and bradykinin overproduction. C1-INH is a heavily glycosylated protein in the serine protease inhibitor (SERPIN) family, yet the role of these glycosylation sites remains unclear. To elucidate the functional impact of N-glycosylation in the SERPIN domain of C1-INH, we engineered 4 sets consisting of 26 variants at or near the N-linked sequon (NXS/T). Among these, 6 are reported in patients with hereditary angioedema and 5 are known C1-INH variants without accessible clinical histories. We systematically evaluated their expression, structure, and functional activity with C1s̄, FXIIa, and kallikrein. Our findings showed that of the 11 reported variants, 7 were deleterious. Deleting N at the 3 naturally occurring N-linked sequons (N238, N253, and N352) resulted in pathologic consequences. Altering these sites by substituting N with A disrupted N-linked sugar attachment, but preserved protein expression and function. Furthermore, an additional N-linked sugar generated at N272 impaired C1-INH function. These findings highlight the importance of N-linked sequons in modulating the expression and function of C1-INH. Insights gained from identifying the pathological consequences of N-glycan variants should assist in defining more tailored therapy.

Rare connective tissue diseases in patients with C1-inhibitor deficiency hereditary angioedema: first evidence on prevalence and distribution from a large Italian cohort study

Introduction

In patients with Hereditary Angioedema (HAE) related to primary C1 inhibitor deficiency (C1INH), the defective clearance of immune complexes and apoptotic materials along with impairment of normal humoral response potentially leads to autoimmunity. Few studies report evidence on autoimmune diseases in C1INH-HAE, but no large population studies focus on rare connective tissue diseases (RCTDs). We aim at evaluating for the first time prevalence and distribution of RCTDs - Systemic Lupus Erytematosus (SLE), primary Sjogren Syndrome (SjS), primary antiphospholipid syndrome (APS), Systemic Sclerosis (SSc), and mixed connective tissue diseases (MCTD) in a large Italian cohort of C1INH-HAE patients.

Methods

A multicenter observational study includes C1INH-HAE patients from ITACA Centers throughout Italy (time frame Sept 2023-March 2024). Inclusion criteria are i. a defined diagnosis of type I or type II C1INH-HAE; ii. age ≥15 years (puberty already occurred); iii. enrollment in the ITACA Registry. The diagnosis of SLE, primary SjS, primary APS, SSc, and MCTD are made in accordance with international classification criteria.

Results

Data are collected from a total of 855 C1INH-HAE patients referring to 15 ITACA Centers. Patients with concomitant RCTDs were 18/855 (2.1%) with F:M ratio 3.5 and a prevalent type I C1INH-HAE diagnosis (87.2%). A diagnosis of SLE results in 44.5% of cases (n=8) while the remaining diagnoses are primary SjS (22.2%, n=4), primary APS (16.6%, n=3), SSc (11.2%, n=2), and a single case of MCTD (5.5%). The female gender is prevalent in all the RCTDs. Patients on long term prophylaxis (LTP) are significantly prevalent in RCTDs group than in the whole C1INH-HAE population (p<0.01).

Conclusions

A relevant prevalence of RCTDs is documented in C1INH-HAE patients, mainly SLE. Patients with RCTDs are on LTP in a significant proportion supporting the idea of a bidirectional link between C1INH-HAE and autoimmunity.

Unveiling the Complexities of Hereditary Angioedema

Hereditary angioedema (HAE) is a rare and potentially life-threatening genetic disorder, constituting approximately 2% of all clinical cases of angioedema, with a global prevalence estimated between 1 in 50,000 and 1 in 150,000 individuals. The condition affects individuals of all genders and ethnic backgrounds without significant variation. HAE is classified into three types. Type I HAE, which accounts for 85% of cases, is characterized by a deficiency of the C1 esterase inhibitor (C1-INH) gene. Type II HAE, making up 15% of cases, involves a dysfunctional C1-INH. Type III HAE, which represents about 5% to 10% of cases, is often estrogen-dependent and although several mutations have been identified, it typically involves normal C1-INH activity. Despite the differences in C1-INH functionality, all three types of HAE manifest with similar clinical symptoms. HAE leads to recurrent episodes of non-pruritic angioedema, which occurs in the absence of urticaria. Breakthroughs in understanding HAE pathophysiology have revolutionized treatment, leading to the development of highly targeted therapies for both acute management and long-term prevention. Meanwhile, cutting-edge advancements in omics technologies are unlocking new possibilities for biomarker discovery, paving the way for more precise diagnoses and personalized treatment strategies that could significantly enhance patient outcomes. This review will delve into the intricate pathophysiology, diverse clinical presentations, and diagnostic challenges of HAE while exploring emerging biomarkers and innovative approaches to therapeutic management and prevention strategies. Additionally, it will underscore the vital importance of screening family members of affected individuals, even when symptoms are not present.

Targeting factor XIIa for therapeutic interference with hereditary angioedema

Hereditary angioedema (HAE) is a rare, potentially life-threatening genetic disorder characterized by recurrent attacks of swelling. Local vasodilation and vascular leakage are stimulated by the vasoactive peptide bradykinin, which is excessively produced due to dysregulation of the activated factor XII (FXIIa)-driven kallikrein-kinin system. There is a need for novel treatments for HAE that provide greater efficacy, improved quality of life, minimal adverse effects, and reduced treatment burden over current first-line therapies. FXIIa is emerging as an attractive therapeutic target for interference with HAE attacks. In this review, we draw on preclinical, experimental animal, and in vitro studies, providing an overview on targeting FXIIa as the basis for pharmacologic interference in HAE. We highlight that there is a range of FXIIa inhibitors in development for different therapeutic areas. Of these, garadacimab, an FXIIa-targeted inhibitory monoclonal antibody, is the most advanced and has shown potential as a novel long-term prophylactic treatment for patients with HAE in clinical trials. The evidence from these trials is summarized and discussed, and we propose areas for future research where targeting FXIIa may have therapeutic potential beyond HAE.

Angioedema as a Presenting Feature in a Patient With SLE: A Case Report

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease that can be easily missed due to its variable presentation. Acquired angioedema (AAE) is a rare first presentation of SLE. We report a case of a 23-year-old woman who presented to the emergency department with rapidly progressive swelling of the tongue and neck, followed by respiratory discomfort and a generalized non-itchy rash. A tracheostomy was performed to relieve her symptoms. Her history, examination, and relevant investigations all indicated SLE. She was treated with high-dose steroids, and pulse therapy with methylprednisolone was given for three days. Hydroxychloroquine was added, but she developed sepsis and an acute flare of SLE secondary to tracheostomy site infection. Subsequently, she was treated with broad-spectrum antibiotics, followed by a tapering dose of steroids and a maintenance dose of azathioprine. She responded to treatment, tracheostomy reversal was performed, and the patient was discharged.

The future of therapeutic options for hereditary angioedema

Hereditary angioedema (HAE) is a rare genetic condition causing unpredictable and severe episodes of angioedema that are debilitating and life-threatening. Moreover, HAE can be classified into HAE due to C1-esterase inhibitor deficiency (HAE-C1INH) or HAE with normal C1INH. Moreover, HAE-C1INH is subcategorized as types I and II based on deficient or dysfunctional circulating C1INH protein resulting from inherited or spontaneous mutations in the SERPING1 gene leading to uncontrolled factor XII/plasma kallikrein activation and excessive bradykinin production. Bradykinin-2 receptor activation leads to vasodilation, increased vascular permeability, and smooth muscle contractions, resulting in subcutaneous or submucosal fluid extravasation that can affect the face, extremities, airway, and gastrointestinal and genitourinary systems. Furthermore, HAE with normal C1INH is caused by either a known or unknown genetic mutation, and the mechanisms are less well-established but most forms are thought to be related to bradykinin signaling with a similar presentation as HAE-C1INH despite normal levels of C1INH protein and function. Current HAE management strategies include on-demand and prophylactic treatments which replace C1INH, reduce kallikrein activity, or block bradykinin binding to the bradykinin B2 receptor. With the advent of additional small molecule inhibitors, monoclonal antibodies, RNA-targeted therapies, gene therapies, and gene modification approaches, preclinical studies and human clinical trials are underway to further expand therapeutic options in HAE. This review article will briefly summarize current HAE treatments and provide an overview of potential future therapies for HAE.

Early Diagnosis of Hereditary Angioedema in Japan Based on a US Medical Dataset: Algorithm Development and Validation

BACKGROUND

Hereditary angioedema (HAE), a rare genetic disease, induces acute attacks of swelling in various regions of the body. Its prevalence is estimated to be 1 in 50,000 people, with no reported bias among different ethnic groups. However, considering the estimated prevalence, the number of patients in Japan diagnosed with HAE remains approximately 1 in 250,000, which means that only 20% of potential HAE cases are identified.

OBJECTIVE

This study aimed to develop an artificial intelligence (AI) model that can detect patients with suspected HAE using medical history data (medical claims, prescriptions, and electronic medical records [EMRs]) in the United States. We also aimed to validate the detection performance of the model for HAE cases using the Japanese dataset.

METHODS

The HAE patient and control groups were identified using the US claims and EMR datasets. We analyzed the characteristics of the diagnostic history of patients with HAE and developed an AI model to predict the probability of HAE based on a generalized linear model and bootstrap method. The model was then applied to the EMR data of the Kyoto University Hospital to verify its applicability to the Japanese dataset.

RESULTS

Precision and sensitivity were measured to validate the model performance. Using the comprehensive US dataset, the precision score was 2% in the initial model development step. Our model can screen out suspected patients, where 1 in 50 of these patients have HAE. In addition, in the validation step with Japanese EMR data, the precision score was 23.6%, which exceeded our expectations. We achieved a sensitivity score of 61.5% for the US dataset and 37.6% for the validation exercise using data from a single Japanese hospital. Overall, our model could predict patients with typical HAE symptoms.

CONCLUSIONS

This study indicates that our AI model can detect HAE in patients with typical symptoms and is effective in Japanese data. However, further prospective clinical studies are required to investigate whether this model can be used to diagnose HAE.

DAB2IP associates with hereditary angioedema: Insights into the role of VEGF signaling in HAE pathophysiology

BACKGROUND

In the recent years, there was an important improvement in the understanding of the pathogenesis of hereditary angioedema (HAE). Notwithstanding, in a large portion of patients with unknown mutation (HAE-UNK) the genetic cause remains to be identified.

OBJECTIVES

To identify new genetic targets associated with HAE, a large Argentine family with HAE-UNK spanning 3 generations was studied.

METHODS

Whole exome sequencing was performed on affected family members to identify potential genetic variants associated with HAE-UNK. In silico analyses and experimental studies were applied to assess the role of the identified gene variant.

RESULTS

A missense variant (p.D239N) in DAB2IP was identified. The variant occurred in the C2-domain, the region interacting with vascular endothelial growth factor receptor 2 (VEGFR2). It was found to be rare, and predicted to have a detrimental effect on the functionality of DAB2IP. Protein structure modeling predicted changes in the mutant p.D239N protein structure, impacting protein stability. The p.D239N variant affected the subcellular localization of VEGFR2. Cells transfected with the DAB2IP-239N transcript exhibited an intracellular distribution, and VEGFR2 remained associated with the cell membrane. The altered localization pattern indicated reduced colocalization of the mutant protein with VEGFR2, suggesting a diminished ability of VEGFR2 binding.

CONCLUSIONS

The study identified a novel missense variant (p.D239N) in DAB2IP in a family with HAE-UNK and highlighted the role of dysregulated VEGF-mediated signaling in altered endothelial permeability. DAB2IP loss-of-function pathogenic variants lead to the impairment of the endothelial VEGF/VEGFR2 ligand system and represent a new pathophysiologic cause of HAE-UNK.

The CC2D2B is a novel genetic modifier of the clinical phenotype in patients with hereditary angioedema due to C1 inhibitor deficiency

Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1-INH) is a rare genetic disorder caused by pathogenic variants in the SERPING1 gene and characterised by swelling and a highly variable clinical phenotype. We aimed to identify novel modifying genetic factors predisposing to the clinical symptoms. We performed whole exome sequencing (WES) and comprehensive bioinformatic analysis in symptomatic and asymptomatic (three duos) family members with HAE-C1-INH. Selected variants identified using WES (present in all asymptomatic and absent in symptomatic patients) were determined using Sanger sequencing. We included 88 clinically well-characterised HAE-C1-INH patients from south-eastern Europe (nine asymptomatic) from 42 unrelated families. We identified 39 variants in 23 genes (ANKRD36C, ARGFX, CC2D2B, IL5RA, IRF2BP2, LGR6, MRPL45, MUC3A, NPIPA1, NRG1, OR5M1, OR5M3, OR5M10, OR8U3, PLCL1, PRSS3, PSKH2, PTPRA, RTP4, SEZ6, SLC25A5, VWA3A, and ZNF790). We selected variants in CC2D2B and PLCL1, which were analysed using Sanger sequencing in the entire group of HAE-C1-INH. We found significant differences in the frequencies of the CC2D2B c.190A>G (rs17383738) variant between symptomatic and asymptomatic patients, where heterozygotes were more common in asymptomatic HAE-C1-INH patients in comparison to symptomatic patients (55 % vs 23%; P = 0.049, OR = 4.24, 95% CI 1.07-14.69). Our study identified novel genetic factors that modify the clinical variability of HAE-C1-INH. We further demonstrated, in a large cohort, the importance of the CC2D2B gene as a disease-modifying factor. Based on linkage disequilibrium analysis, the CCNJ and ZNF518A genes might also be involved in the clinical variability of HAE-C1-INH.

Contact System Activation and Bradykinin Generation in Angioedema: Laboratory Assessment and Biomarker Utilization

The role of contact system activation has been clearly established in the pathogenesis of hereditary angioedema due to C1 inhibitor deficiency (HAE-C1INH). C1 inhibitor (C1INH)-protease complexes, levels of functional C1INH, plasma kallikrein activation, and cleavage of high-molecular-weight kininogen have each been associated with disease activity. More recently, HAE with normal levels of C1INH (HAE-nl-C1INH) has been recognized. Six genetic mutations have been identified which are linked to HAE-nl-C1INH phenotypes. The majority of individuals with HAE-nl-C1INH fall into the unknown category. There is substantial evidence that bradykinin generation underlies the recurrent attacks of swelling in some of these cohorts.

Classification, Diagnosis, and Pathology of Angioedema Without Hives

A clear disease classification schema coupled with an understanding of the specific mechanisms involved in the different types of angioedema without hives informs the diagnostic assessment. The recommended approach involves several key steps. Foremost is the recognizing of the clinical clues which allow for the differentiation of mast cell-mediated disorders from bradykinin-mediated angioedema. Enhanced vascular permeability related to bradykinin is of critical importance to identify given the implications for disease morbidity and risk of mortality. The ability to efficiently categorize and diagnose all forms of angioedema results in improved patient outcomes.

Epidemiology, economic, and humanistic burden of hereditary angioedema: a systematic review

BACKGROUND

This systematic study aims to assess the global epidemiologic, economic, and humanistic burden of illness associated with all types of hereditary angioedema.

METHODS

A systematic search for articles reporting the epidemiologic, economic, and humanistic burden associated with patients with HAE was conducted using English and Chinese literature databases from the inception to May 23, 2022. The selected studies were assessed for their quality and risk of bias. The study was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022352377).

RESULTS

In total, 65 articles that met the search inclusion criteria reported 10,310 patients with HAE, of whom 5861 were female patients. Altogether, 4312 patients (81%) and 479 patients (9%) had type 1 and type 2 HAE, respectively, whereas 422 patients (8%) had HAE-normal C1-INH. The overall prevalence of all types of HAE was between 0.13 and 1.6 cases per 100,000. The mean or median delay from the first onset of a symptom of HAE to confirmed diagnosis ranged from 3.9 to 26 years. The estimated risk of death from asphyxiation was 8.6% for patients with HAE. Hospitalization, medication, unnecessary surgeries, doctor visits, specialist services, and nursing costs are direct expenses that contribute to the growing economic burden. The indirect cost accounted mostly due to missing work ($3402/year) and loss of productivity ($5750/year). Furthermore, impairment of QoL as reported by patient-reported outcomes was observed. QoL measures identified depression, anxiety, and stress to be the most common symptoms for adult patients and children.

CONCLUSION

This study highlights the importance of early diagnosis and the need for improving awareness among health care professionals to reduce the burden of HAE on patients and society.

Navigating the swells: A case report of hereditary angioedema

Hereditary angioedema (HAE) is a rare genetic disorder characterized by recurrent episodes of localized edema caused by a deficiency or dysfunction of C1 inhibitor (C1-INH). This case report presents the clinical features, diagnostic evaluation, and management of a 23-year-old man with HAE. We discuss the challenges of diagnosing and treating this condition, emphasizing the importance of early recognition and appropriate therapeutic interventions.

An Overview of Hereditary Angioedema for the Primary Care Physician

Hereditary angioedema is a rare autosomal dominant condition characterized by episodes of swelling of the upper airway, intestines, and skin. The disorder is characterized by deficiency in C1 esterase inhibitor (C1-INH) or a decrease in functional C1-INH. Treatment options include on demand therapy (treatment of acute attacks), long-term prophylaxis, and short-term prophylaxis. Corticosteroids, epinephrine, and antihistamines are not effective for this form of angioedema. The high mortality in patients undiagnosed underscores a need for broader physician awareness to identify these patients and initiate therapy.

Garadacimab for hereditary angioedema attack prevention: long-term efficacy, quality of life, and safety data from a phase 2, randomised, open-label extension study

BACKGROUND

Garadacimab is a fully human immunoglobulin G4 monoclonal antibody targeting activated factor XII. This study evaluated long-term efficacy, health-related quality of life (HRQoL), and safety data for garadacimab in adults with hereditary angioedema.

METHODS

This global phase 2 study comprised a treatment period 1 (TP1: 12 weeks, double-blind, placebo-controlled) and a treatment period 2 (TP2: ≥44-week open-label extension). Patients aged 18-65 years with clinically confirmed hereditary angioedema were eligible. In TP1, 32 patients were randomly assigned (1:1:1:1) to receive subcutaneous garadacimab (75 mg, 200 mg, or 600 mg) or placebo every 4 weeks (once monthly). Randomisation was done using interactive response technology via block randomisation (block sizes 1-4). Subsequently, six additional patients in TP1 were assigned to open-label garadacimab 400 mg every 2 weeks. At the start of TP2, patients were re-randomised (if receiving placebo, garadacimab 75 mg, or garadacimab 400 mg) or continued to receive garadacimab 200 mg or garadacimab 600 mg once monthly. After a protocol amendment on March 20, 2020, patients originally assigned to the 600 mg dose were down-titrated to 200 mg at their next visit. The primary endpoint (published previously) was monthly attack rate for patients receiving 200 mg or 600 mg garadacimab in TP1 in the intention-to-treat population. Here, we assessed the impact of garadacimab on patient-reported and investigator-reported outcomes and HRQoL as well as long-term efficacy and safety. This trial is registered with ClinicalTrials.gov, NCT03712228, and is completed.

FINDINGS

Of 54 patients screened between Oct 29, 2018, and Aug 28, 2019, 32 randomised and six open-label patients completed TP1 and entered TP2 (20 in the garadacimab 200 mg group; 18 in the garadacimab 600 mg group; total 38 patients). Median age was 39·0 years (IQR 27·0-53·0), and 21 patients (55%) were female and 17 (45%) were male. In TP2, the median garadacimab exposure was 87·9 weeks (IQR 50·0-106·6) in the garadacimab 200 mg group and 44·1 weeks (24·1-56·1) in the garadacimab 600 mg group. Median monthly attack rates were 0·0 (IQR 0·0-0·1) in the garadacimab 200 mg group and 0·1 (0·0-0·4) in the garadacimb 600 mg group. Median reduction in monthly attack rate versus run-in was 100% (IQR 98-100) with garadacimab 200 mg. HRQoL improvements observed during TP1 with garadacimab were sustained throughout TP2. TP2 safety signals were consistent with TP1. Two patients experienced serious adverse events of diverticular perforation and asthma (not garadacimab-related). Treatment-emergent adverse events were mostly mild or moderate in severity. The most common adverse events were headache (nine of 38, 24%) and abdominal pain (seven of 38, 18%). There were no treatment-related deaths.

INTERPRETATION

Once-monthly garadacimab for more than 2 years in patients with hereditary angioedema was well tolerated and efficacious in reducing monthly attack rate and improving HRQoL. These results reveal the potential of long-term prophylactic treatment with 200 mg once-monthly garadacimab towards complete disease control of patients with hereditary angioedema.

FUNDING

CSL Behring.

Clinical Progress in Hepatic Targeting for Novel Prophylactic Therapies in Hereditary Angioedema

Hereditary angioedema (HAE) is typically caused by a deficiency of the protease inhibitor C1 inhibitor (C1INH). The absence of C1INH activity on plasma kallikrein and factor XIIa leads to overproduction of the vasoactive peptide bradykinin, with resulting angioedema. As the primary site of C1INH and prekallikrein production, the liver is recognized as an important therapeutic target in HAE, leading to the development of hepatic-focused treatment strategies such as GalNAc-conjugated antisense technology and gene modification. This report reviews currently available data on hepatic-focused interventions for HAE that have advanced into human trials. Donidalorsen is an investigational GalNAc3-conjugated antisense oligonucleotide that binds to prekallikrein mRNA in the liver and reduces the expression of prekallikrein. Phase 2 data with subcutaneous donidalorsen demonstrated a significant reduction in HAE attack rate compared with placebo. Phase 3 trials are underway. ADX-324 is a GalNAc3-conjugated short-interfering RNA being investigated in HAE. BMN 331 is an investigational AAV5-based gene therapy vector that expresses wild-type human C1INH and is targeted to hepatocytes. A single intravenous dose of BMN 331 is intended to replace the defective SERPING1 gene and enable patients to produce functional C1INH. A first-in-human phase 1/2 study is ongoing with BMN 331. NTLA-2002 is an investigational in vivo clustered regularly interspaced short palindromic repeats/Cas9-based therapy designed to knock out the prekallikrein-coding KLKB1 gene in hepatocytes; a phase 1/2 study is ongoing. Findings from these and other ongoing studies are highly anticipated with the expectation of expanding the array of treatment options in HAE.

Recurrent Isolated Uvular Angioedema Associated With Intranasal Cocaine Use: A Case Report

Isolated uvular angioedema, or Quincke's disease, is a rare manifestation with various potential causes. This article presents the first documented case of recurrent isolated uvular angioedema associated with intranasal cocaine use. The patient, a 43-year-old man, exhibited acute symptoms of sore throat, throat swelling, and difficulty breathing, with a history of a similar episode a few years prior. Both episodes occurred following intranasal cocaine use. Examination revealed an enlarged uvula obstructing the airway. The patient was treated with epinephrine, antihistamines, and corticosteroids with resolution of the uvular edema. This case highlights the importance of considering cocaine as a potential causative agent in isolated uvular angioedema and emphasizes the need for patient education to avoid further cocaine use.

Clinical Characteristics and Quality of Life in a Cohort of Polish Pediatric Patients with Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disease. It is characterized by recurrent attacks of angioedema. Evidence to what extent it affects patient functioning is limited in the pediatric population. We aimed to determine the clinical characteristics and management of Polish children with HAE and to measure the health-related quality of life (HRQoL) of these patients. This cross-sectional study was conducted among 21 pediatric patients and their caregivers, as well as 21 respective controls randomly selected from the general population. During routine follow-up visits, standardized pediatric quality of life questionnaires (PedsQLTM 4.0) were administered to all caregivers and adolescents (≥13 years). Caregivers also completed a structured medical interview regarding the clinical characteristics and treatment of children with HAE during the previous six months. During this period, 57% of patients had low (group I), 24% moderate (group II), and 19% high (group III) HAE activity, corresponding to ≥10 attacks per 6 months. None of the patients received long-term prophylaxis. The children in group III had a lower HRQoL than other groups and controls on all dimensions of the PedsQLTM 4.0. The lowest scores in all groups were observed in the emotional functioning domain. Our data demonstrate that the burden of HAE on the quality of life of pediatric patients and their families encompasses a wide range of daily functioning.

The bradykinin-forming cascade in anaphylaxis and ACE-inhibitor induced angioedema/airway obstruction

Anaphylaxis is a potentially life-threatening multi-system allergic reaction to a biological trigger resulting in the release of potent inflammatory mediators from mast cells and basophils and causing symptoms in at least two organ systems that generally include skin, lungs, heart, or gastrointestinal tract in any combination. One exception is profound hypotension as an isolated symptom. There are two types of triggers of anaphylaxis: immunologic and non-Immunologic. Immunologic anaphylaxis is initiated when a foreign antigen directly binds to IgE expressed on mast cells or basophils and induces the release of histamine and other inflammatory substances resulting in vasodilation, vascular leakage, decreased peripheral vascular resistance, and heart muscle depression. If left untreated, death by shock (profound hypotension) or asphyxiation (airway obstruction) can occur. The non-immunologic pathway, on the other hand, can be initiated in many ways. A foreign substance can directly bind to receptors of mast cells and basophils leading to degranulation. There can be immune complex activation of the classical complement cascade with the release of anaphylatoxins C3a and C5a with subsequent recruitment of mast cells and basophils. Finally, hyperosmolar contrast agents can cause blood cell lysis, enzyme release, and complement activation, resulting in anaphylactoid (anaphylactic-like) symptoms. In this report we emphasize the recruitment of the bradykinin-forming cascade in mast cell dependent anaphylactic reactions as a potential mediator of severe hypotension, or airway compromise (asthma, laryngeal edema). We also consider airway obstruction due to inhibition of angiotensin converting enzyme with a diminished rate of endogenous bradykinin metabolism, leading not only to laryngeal edema, but massive tongue swelling with aspiration of secretions.

Sirolimus potentiated angioedema: A case report and review of the literature

Introduction

In the realm of organ transplantation, particularly heart transplantation, angioedema presents a significant challenge. This clinical condition ranges from minor facial edema to life-threatening swelling of vital structures. Its multifactorial etiology involves various factors and mechanisms, including C1 esterase inhibitor deficiency, food allergen hypersensitivity, and adverse drug reactions, notably involving angiotensin-converting enzyme (ACE) inhibitors and mechanistic target of rapamycin inhibitors (mTOR-Is). We present a rare case of sirolimus potentiated angioedema in a patient with long-standing ACE inhibitor therapy.

Case

A 52-year-old male with a history of heart transplant developed severe upper and lower lip edema. The patient had been on Lisinopril without any adverse events. However, sirolimus was recently added to his drug regimen. Sirolimus potentiated angioedema was suspected.

Intervention

Intravenous methylprednisolone, famotidine, and diphenhydramine were initiated, and both lisinopril and sirolimus were discontinued. The patient showed improvement and was discharged with oral antihistamines.

Lessons

Transplant physicians should be aware of the life-threatening interaction between ACE inhibitors and mTOR-Is like sirolimus. Consideration should be given to switching from an ACE inhibitor to an angiotensin-receptor blocker when initiating patients on mTOR-Is.

The US Hereditary Angioedema Association Scientific Registry: hereditary angioedema demographics, disease severity, and comorbidities

BACKGROUND

Hereditary angioedema (HAE) and idiopathic nonhistaminergic angioedema (INHA) are ultra-rare diseases whose natural histories and comorbidities are incompletely understood.

OBJECTIVE

To develop a national patient-centric registry to address these deficiencies in our knowledge and improve our ability to assess the real-world impact of therapeutic interventions.

METHODS

Data from members of the US HAE Association were collected into an online registry between 2009 and April 7, 2021. Cohorts were categorized by reported physician diagnosis. Patient reported data were collected using a series of questionnaires. Demographic, natural history, and family history outcomes of the HAE due to C1 inhibitor deficiency (HAE-C1INH) participants were compared with those of the combined HAE with normal C1 inhibitor (HAE-nl-C1INH) plus INHA group. The prevalence of comorbid conditions in the HAE-C1INH group was compared with the general US population.

RESULTS

A total of 485 HAE-C1INH, 26 HAE-nl-C1INH, and 70 INHA participants were included in the analysis. Delay to diagnosis was shorter in HAE-C1INH (5 vs 11 years), but both had decreasing delays over time. Differences in attack frequency and location were found between the groups. Morbidity surrogates including emergency department visits, hospitalizations, unnecessary abdominal surgeries, and intubations were strikingly high as was mortality with 36.9% of HAE-C1INH and 15.4% of HAE-nl-C1INH participants reporting family members who died from a HAE attack. Females with HAE-C1INH had a significant increase in the prevalence of depression, sleep disorders, kidney disease, anemia, and hepatitis. Cardiovascular comorbidities were significantly reduced in the HAE-C1INH group.

CONCLUSION

The US HAEA Scientific Registry provides a mechanism to enhance our knowledge of HAE and INHA.

Epidemiology and treatment of children with hereditary angioedema in Germany: A retrospective database study

BACKGROUND

Hereditary angioedema (HAE) is a potentially life-threatening inherited disease that causes recurrent, serious, and debilitating episodes of swelling. While evidence has improved in adult patients, data on the epidemiology and treatment of pediatric patients with HAE remain very limited. The aim of this study was to determine the incidence and prevalence of pediatric patients with HAE aged <12 years, as well as treatment patterns, co-medication, and specialties involved.

METHODS

In this retrospective study (2016-2021), the German IQVIATM pharmacy claims (LRx) database was used to analyze prescriptions of HAE-specific treatments and co-medications.

RESULTS

We found an HAE prevalence in pediatric patients aged <12 years of 2.51:100,000 and a 12-month prevalence of up to 1.02:100,000 between 2016 and 2021. Most HAE treatments were prescribed by outpatient clinics and pediatricians, with an increasing proportion of icatibant as an on-demand treatment and low rates of long-term prophylaxis (LTP). The prescription rate of analgesics as the most common co-medication decreased notably after HAE diagnosis.

CONCLUSION

Our findings provide insights into the epidemiology and current pediatric HAE treatment landscape in Germany. The obtained HAE prevalence in pediatric patients aged <12 years was even higher than the previously reported average of overall cohorts, whereas the LTP rate was low, which might indicate an unmet need for newer LTP treatment options in pediatric patients.

Angiotensin-Converting Enzyme Inhibitors and Other Medications Associated With Angioedema

Angioedema is a localized swelling of the dermis, subcutaneous tissues, and/or submucosal tissues caused by fluid extravasation into these tissues. Angioedema is associated with certain vasoactive molecules and is typically mediated by histamine or bradykinin. It manifests clinically as facial edema, swelling of the extremities and urogenital area, and potential involvement of the larynx, leading to dyspnea and inspiratory stridor, which can become life-threatening. Histamine-mediated angioedema is associated with urticaria and pruritus and will show classic signs of allergic (type 1 hypersensitivity) reactions. Bradykinin-mediated angioedema is often familial (hereditary angioedema) and is more often associated with gastrointestinal symptoms (abdominal pain, nausea, vomiting, diarrhea), edema of the extremities and trunk, and a lack of urticaria and pruritus. Angiotensin-converting enzyme inhibitors (ACEIs) are a class of medications commonly prescribed for hypertension, heart failure, and diabetic nephropathy. ACEIs are associated with an increased risk of angioedema, which can range from a mild reaction to severe and life-threatening. ACEI-induced angioedema is a bradykinin-mediated reaction that can occur in individuals with a genetic predisposition. Other medications, such as angiotensin receptor blockers, nonsteroidal anti-inflammatory drugs, and certain antibiotics, most notably those in the beta-lactam class, can also cause drug-induced angioedema. The present investigation describes current knowledge of the pathophysiology, epidemiology, clinical manifestations, predisposing factors, and management of drug-induced angioedema.

Pathophysiology of bradykinin and histamine mediated angioedema

Angioedema is characterized by swelling localized to the subcutaneous and submucosal tissues. This review provides an overview of angioedema, including the different types, triggers, and underlying pathophysiologic mechanisms. Hereditary and acquired angioedema are caused by dysregulation of the complement and kinin pathways. In contrast, drug-induced and allergic angioedema involve the activation of the immune system and release of vasoactive mediators. Recent advances in the understanding of the pathophysiology of angioedema have led to the development of targeted therapies, such as monoclonal antibodies, bradykinin receptor antagonists, and complement inhibitors, which promise to improve clinical outcomes in patients with this challenging condition. To accurately diagnose and manage angioedema, an understanding of this condition's complex and varied pathophysiology is both necessary and critical.

The Importance of Patient Empowerment: A Clinical Case of Hereditary Angioedem

Hereditary angioedema (HAE) is a rare condition characterized by recurrent episodes of angioedema without urticaria or pruritus. Untreated angioedema can cause significant work absenteeism and, in rare cases, be lethal due to laryngeal involvement and suffocation. The authors report a case of a patient with laryngeal involvement who was unaware of the severity of their condition. Effective medical training in patient empowerment is essential, and it is an irreplaceable element in healthcare, as it contributes to therapeutic success.

A Comprehensive Management Approach in Pediatric and Adolescent Patients With Hereditary Angioedema

Hereditary angioedema (HAE) is a rare autosomal-dominant disorder; most cases are characterized by low plasma levels of C1 esterase inhibitor (C1-INH). Clinical manifestations of HAE due to C1-INH deficiency include unpredictable, acute, recurrent episodes of nonpruritic swelling that can affect the face, trunk, limbs, and the respiratory, gastrointestinal, and genitourinary tracts. Attacks can be disfiguring, disabling, painful, and even life-threatening if laryngeal swelling occurs. Symptoms of HAE generally manifest in childhood. Effective medications are available and approved to treat HAE in children. However, evidence informing use of these medications in pediatric clinical practice is limited. Hereditary angioedema management plans are critical to optimize outcomes and should address on-demand treatment for acute attacks and plans to prevent potentially fatal laryngeal attacks. The plan should also comprise a holistic approach to address nonclinical aspects of HAE, including quality of life (QoL) and psychological issues. This article provides an overview of HAE management principles that health care providers can apply to treat pediatric patients to improve their QoL.

Gene Therapy for Immunoglobulin E, Complement-Mediated, and Eosinophilic Disorders

Immunoglobulin E, complement, and eosinophils play an important role in host defense, but dysfunction of each of these components can lead to a variety of human disorders. In this review, we summarize how investigators have adapted gene therapy and antisense technology to modulate immunoglobulin E, complement, and/or eosinophil levels to treat these disorders.

Real-world experience of hereditary angioedema (HAE) in Mexico: A mixed-methods approach to describe epidemiology, diagnosis, and treatment patterns

Introduction and objectives

Due to the lack of structured and systematic information available, the aim of this study was to describe the epidemiology, diagnosis, healthcare processes, and treatment patterns of hereditary angioedema (HAE) in Mexico. To achieve this, different data sources were consulted regarding medical literature, structured health system databases, and angioedema-specialized physicians (AEP) opinion regarding HAE.

Material and methods

A mixed methods approach was conducted in 4 phases: I) systematic literature review (SLR) and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines; II) review of national health system (NHS) databases and systematic reports; III) physician survey; and IV) an epidemiologic model. ICD 10 D84.1 encoded records from the NHS were used to estimate the number of patients with HAE attended and treated during 2019. A survey was implemented to increase understanding of the clinical profile and treatments used.

Results

A prevalence rate of 0.9/50 000 inhabitants was estimated for 2019. In the same year, an estimated 317 HAE type 1 patients were recorded in the NHS, aged ≥11 years old. The most frequent clinical symptoms were cutaneous edema (67.5%) and abdominal pain (47.9%). A severe episode with laryngeal edema appeared in 27.5% of cases. Acute episodes were mainly moderate to severe (77.0%), with an annual per capita frequency of emergency visits of 7.6 patient-year (range 1-12/patient-year). The main reasons for hospitalization corresponded to laryngeal facial, tongue, and abdominal edemas, representing 73.3% of annual ICD 10 D84.1 reported hospitalizations. The main treatments that patients with HAE received were fresh frozen plasma for acute attacks and danazol for short-term prophylaxis (STP).

Conclusions

Despite efforts to make HAE visible, according to this study, cases recognized and treated in the NHS represent only 16.6% of the estimated prevalence.

Hereditary Angioedema: A Review of the Current and Evolving Treatment Landscape

Hereditary angioedema (HAE) is a rare disease characterized by sudden and often unprovoked episodes of swelling that can be potentially life-threatening when it involves the upper airway. The treatment options for both acute episodes of HAE and LTP, used to minimize the frequency and severity of angioedema attacks, were limited historically to very few options, had considerable side effects, and/or had considerable burden of treatment. Fortunately, through the elucidation of the pathophysiology of HAE, the development of newer targeted therapies has been possible both for acute therapy and long-term prophylaxis and even more are on the horizon. Because of the rapid development of these therapies, it can be challenging for clinicians to keep abreast of newer and developing treatments for HAE. This review article will outline the current and potential future treatments for HAE. It will also highlight important considerations when treating special HAE patient populations including women and pediatric patients.

Genetic Variants Leading to Urticaria and Angioedema and Associated Biomarkers

Advances in next generation sequencing technologies, as well as their expanded accessibility and clinical use over the past 2 decades, have led to an exponential increase in the number of identified single gene disorders. Among these are primary atopic disorders-inborn errors of immunity resulting in severe allergic phenotypes as a primary presenting feature. Two cardinal aspects of type I immediate hypersensitivity allergic reactions are hives and angioedema. Mast cells (MCs) are frequent primary drivers of these symptoms, but other cells have also been implicated. Even where MC degranulation is believed to be the cause, mediator-induced symptoms may greatly vary among individuals. Angioedema-particularly in the absence of hives-may also be caused by hereditary angioedema conditions resulting from aberrant regulation of contact system activation and excessive bradykinin generation or impairment of vascular integrity. In these patients, swelling can affect unpredictable locations and fail to respond to MC-directed therapies. Genetic variants have helped delineate key pathways in the etiology of urticaria and nonatopic angioedema and led to the development of targeted therapies. Herein, we describe the currently known inherited and acquired genetic causes for these conditions, highlight specific features in their clinical presentations, and discuss the benefits and limitations of biomarkers that can help distinguish them.

The impact of puberty on the onset, frequency, location, and severity of attacks in hereditary angioedema due to C1-inhibitor deficiency: A survey from the Italian Network for Hereditary and Acquired Angioedema (ITACA)

INTRODUCTION

Hereditary angioedema due to C1-inhibitor deficiency is influenced by hormonal factors, with a more severe course of disease in women. Our study aims to deepen the impact of puberty on onset, frequency, location and severity of attacks.

METHODS

Retrospective data were collected through a semi-structured questionnaire and shared by 10 Italian reference centers of the Italian Network for Hereditary and Acquired Angioedema (ITACA).

RESULTS

The proportion of symptomatic patients increased significantly after puberty (98.2% vs 83.9%, p=0.002 in males; 96.3% vs 68,4%, p<0.001 in females); the monthly mean of acute attacks was significantly higher after puberty, and this occurred both in females (median (IQR) = 0.41(2) in the three years before puberty vs 2(2.17) in the three years after, p<0.001) and in males (1(1.92) vs 1.25(1.56) respectively, p<0.001). The increase was greater in females. No significant differences were detected in attack location before and after puberty.

DISCUSSION

Overall, our study confirms previous reports on a more severe phenotype in the female gender. Puberty predisposes to increased numbers of angioedema attacks, in particular in female patients.

Insights into the pathogenesis of hereditary angioedema using genetic sequencing and recombinant protein expression analyses

BACKGROUND

The pathogenesis of hereditary angioedema (HAE) type I and type II is linked to defective C1 esterase inhibitor (C1-INH) encoded by the SERPING1 gene. There are substantial variabilities in the clinical presentations of patients with HAE that are not directly correlated to the serum levels of C1-INH. The impact of SERPING1 variants on C1-INH expression, structure, and function is incompletely understood.

OBJECTIVE

To investigate the influence of SERPING1 variants on the C1-INH expression, structure, and function of 20 patients with HAE from 14 families with no prior genetic diagnosis.

METHODS

Patients underwent whole-exome sequencing (WES). If no variants were identified, whole-genome sequencing (WGS) was performed. Except for the frameshift and large deletions, each C1-INH variant was recombinantly produced and, if synthesized and secreted, was subjected to structural, oligosaccharide, and functional analyses.

RESULTS

We identified 11 heterozygous variants in the SERPING1 gene, of which 5 were classified as pathogenic (E85Dfs∗63, N166Qfs∗91, K201Qfs∗56, P399A, and R466H) and 6 as variants of uncertain significance (C130W, I224S, N272del, K273del, L349F, and F471C). Three large heterozygous deletions were discovered through WGS. Our data indicate that C130W, N272del, P399A, and F471C are poorly synthesized, I224S prevents proper C1-INH folding, and K273del impairs C1-INH function by adding an additional oligosaccharide. Further evaluation suggests that compound variant P399A/L349F contributes to a more severe clinical phenotype.

CONCLUSIONS

Our combined approach of WES and WGS uncovered SERPING1 gene alternations in each patient. The recombinant protein production followed by systematic antigenic, structural, and functional assessment facilitates the identification of underlying pathogenic mechanisms in HAE.

[Hereditary angioedema and its new treatments: An update]

Hereditary angioedema, with or without deficient C1 inhibitor level or function, is a rare disease characterized by recurrent attacks of noninflammatory subcutaneous and/or submucosal edema. It may be life-threatening and substantially affects quality of life. Attacks may be spontaneous or induced, in a setting of emotional stress, by infections or physical trauma, in particular. As the key mediator is bradykinin, this angioedema does not respond to the usual treatments of mast cell-mediated angioedema (antihistamines, corticosteroids, adrenaline), which is much more frequent. Therapeutic management of hereditary angioedema first consists in treating severe attacks with a selective B2 bradykinin receptor antagonist or a C1 inhibitor concentrate. The latter or an attenuated androgen (danazol) can be used for short-term prophylaxis. Therapeutic solutions conventionally proposed for long-term prophylaxis (danazol, antifibrinolytics [tranexamic acid], C1 inhibitor concentrate) vary in efficacy and/or pose problems of safety or ease of use. Kallikrein inhibitors (subcutaneous lanadelumab, oral berotralstat) recently made available as disease-modifying treatment constitute an important advance in long-term prophylaxis of hereditary angioedema attacks. The advent of these new drugs is accompanied by a new ambition for patients: optimize control of the disease and thereby minimize its impact on quality of life.

A narrative review of recent literature of the quality of life in hereditary angioedema patients

Hereditary angioedema (HAE) is a rare disorder that causes unpredictable and debilitating cutaneous and submucosal edema and can lead to death. HAE can impair patients' ability to perform daily activities, proportional to pain severity, with patients reporting lower productivity, missed time from work or school and potentially resulting in missed career and educational opportunities. Many patients with HAE experience a significant psychological burden, including anxiety and depression. Available treatment aims to prevent and/or treat HAE attacks as they occur, to reduce morbidity and mortality and, finally, to improve health-related quality of life. Two different validated specific angioedema instruments are available to assess patients' quality of life. The Angioedema Quality of Life Questionnaire (AE-QoL) examines diagnosed patients' quality of life but is not specific for HAE. The disease-specific questionnaire is the Hereditary Angioedema Quality of Life (HAE-QoL), and the first used for hereditary angioedema with C1 inhibitors (C1-INH) deficiency. These quality-of-life instruments are helpful to the HAE patients' assessment and to the development of better therapeutic strategies as clinical tools, as defined by international guidelines. Considering this context, this review was conducted to compare the effects of acute vs. long-term prophylaxis on HAE patients' health-related quality of life. In addition, the prevalence of anxiety and depression among these individuals was also reviewed.

Hereditary Angioedema: Diagnosis, Clinical Implications, and Pathophysiology

Hereditary angioedema (HAE) is an autosomal dominant disorder caused by a mutation in the C1 esterase inhibitor gene. HAE affects 1/50,000 people worldwide. Three main types of HAE exist: type I, type II, and type III. Type I is characterized by a deficiency in C1-INH. C1-INH is important in the coagulation complement, contact systems, and fibrinolysis. Most HAE cases are type I. Type I and II HAE result from a mutation in the SERPING1 gene, which encodes C1-INH. Formally known as type III HAE is typically an estrogen-dependent or hereditary angioedema with normal C1-INH activity. Current guidelines now recommend subdividing hereditary angioedema with normal C1 esterase inhibitor gene (HAE-nl-C1-INH formerly known as HAE type III) based on underlying mutations such as in kininogen-1 (HAE-KNG1), plasminogen gene (PLG-HAE), myoferlin gene mutation (MYOF-HAE), heparan sulfate-glucosamine 3-sulfotransferase 6 (HS3ST6), mutation in Hageman factor (factor XII), and in angiopoietin-1 (HAE-ANGPT-1). The clinical presentation of HAE varies between patients, but it usually presents with nonpitting angioedema and occasionally abdominal pain. Young children are typically asymptomatic. Those affected by HAE usually present with symptoms in their early 20s. Symptoms can arise as a result of stress, infection, or trauma. Laboratory testing shows abnormal levels of C1-INH and high levels of bradykinin. C4 and D-dimer levels can also be monitored if an acute HAE attack is suspected. Acute treatment of HAE can include IV infusions of C1-INH, receptor antagonists, and kallikrein inhibitors. Short- and long-term prophylaxis can also be administered to patients with HAE. First-line therapies for long-term prophylaxis also include IV infusion of C1-INH. This review aims to thoroughly understand HAE, its clinical presentation, and how to treat it.

Phenotypic and Genotypic Characterization of Hereditary Angioedema in Saudi Arabia

Hereditary angioedema (HAE) is a potentially life-threatening autosomal dominant disorder affecting roughly 1:50,000 individuals. It is commonly characterized by swelling of the larynx, gastrointestinal tract, extremities, and skin. There is growing genetic heterogeneity associated with this disease but more than 95% of mutations are found in SERPING1, the gene which encodes complement 1 inhibitor (C1-INH). HAE cohorts from several populations have been published but no large scale study has been reported from the Arab world to date. Here we document the clinical and genetic findings of HAE patients from a single Saudi institution, which is a major referral center at the national level. A total of 51 patients across 17 unrelated families were recruited including two large multi-generational families, of which one contained an in-frame exonic deletion that was resolved through MLPA. Two cases were negative for all the genes we tested (including F12, PLG, ANGPT1, MYOF, KNG1, and HS3ST6). The predominant HAE subtype in our cohort was type I, at 76%. We were able to uncover a mutation in 49 patients (96%). No type III (normal C1-INH) patients were encountered in the clinic, suggesting that this subtype does not play a major role in HAE pathogenesis in Saudi Arabia. Additionally, the existence of four patients with consistently normal complement 4 (C4) levels alongside abnormal C1-INH profiles highlights the utility of dual screening for both proteins in suspected patients.

Hereditary Angioedema

Hereditary angioedema is a rare autosomal dominant condition characterized by episodes of swelling of the upper airway, intestines, and skin. The disorder is characterized by deficiency in C1 esterase inhibitor (C1-INH) or a decrease in functional C1-INH. Treatment options include on demand therapy (treatment of acute attacks), long-term prophylaxis, and short-term prophylaxis. Corticosteroids, epinephrine, and antihistamines are not effective for this form of angioedema. The high mortality in patients undiagnosed underscores a need for broader physician awareness to identify these patients and initiate therapy.

Burden of illness seen in hereditary angioedema in Japanese patients: Results from a patient reported outcome survey

Hereditary angioedema (HAE) is a potentially life-threatening rare disease, which is mainly caused by the deficiency or dysfunction of C1-esterase inhibitor, and characterized by spontaneous, recurrent episodes of edema in various parts of the body including internal organs and the laryngeal area. Delayed diagnosis and treatment increase the burdens and risks of this condition. The current study aimed to understand the burden of illness for HAE patients in Japan before and after diagnosis through a patient reported outcome survey. A survey instrument was distributed to 121 adult patients with HAE by a patient organization via HAE treating physicians between July and November in 2016. Seventy patients (57.9%) returned the questionnaire. Patients reported high levels of medical resource utilization, including emergency procedures and services. Episodes of receiving laparotomy were somewhat less after diagnosis with HAE than before, but no apparent difference in episodes of tracheotomy between before and after the diagnosis. The economic burden, including direct and indirect medical costs, was highest before diagnosis, but still perceived as substantial after diagnosis. Patients reported disruption of work and school life, with 40% reporting that they miss 10 or more days from work or education per year. Sixty percent of patients reported that HAE affected their daily activities. We concluded that HAE is associated with considerable physical, social, economic and psycho-social burdens even after diagnosis, and that higher attack frequency is associated with a heavy disease burden for patients in Japan.

Consensus on diagnosis and management of Hereditary Angioedema in the Middle East: A Delphi initiative

Background

Hereditary angioedema (HAE), a potentially life-threatening genetic disorder due to C1 inhibitor deficiency in most cases, is characterized by sudden and/or recurrent attacks of angioedema (subcutaneous/submucosal swellings). The global World Allergy Organization (WAO)/European Academy of Allergy and Clinical Immunology (EAACI) International guideline for HAE management is comprehensive, but the implementation of this guideline may require regional adaptation considering the diversity in disease awareness, type of medical care systems, and access to diagnostics and treatment. The aim of this Delphi initiative was to build on the global guideline and provide regional adaptation to address the concerns and specific needs in the Middle East.

Methods

The Consensus panel comprised 13 experts from the Middle East (3 from the United Arab Emirates, 3 from Saudi Arabia, 2 from Lebanon, 2 from Kuwait, 2 from Oman and 1 from Qatar) who have more than 2 decades of experience in allergy and immunology and are actively involved in managing HAE patients. The process that was carried out to reach the consensus recommendation included: 1.) A systematic literature review for articles related to HAE management using Ovid MEDLINE. 2.) The development of a questionnaire by an internationally acclaimed expert, with 10 questions specific to HAE management in the Middle East. 3.) Experts received the questionnaire via email individually and their answers were recorded (email/interview). 4.) A virtual consensus meeting was organized to discuss the questionnaire, make amends if needed, vote, and achieve consensus.

Results

The questionnaire comprised 10 questions, each with 2 or more statements/recommendations on which the regional experts voted. A consensus was reached based on a 70% agreement between the participants. The key highlights include: 1) HAE experts in the Middle East emphasized the importance of a positive family history for arriving at a diagnosis of HAE. 2) The number of episodes per month or per 6-month period and severity should be used, together with other markers, to determine the need for prophylaxis. 3) Disease status should be monitored by periodic visits and the use of patient-reported outcome measures such as the angioedema activity score and the angioedema control test. 4) Attenuated androgens and tranexamic acid may be considered for long-term prophylaxis, if lanadelumab, C1-Inhibitor or berotralstat are not available.

Conclusion

This consensus recommendation may help to educate healthcare practitioners in the Middle East and unify their approach to the diagnosis and management of HAE.

Hereditary angioedema

Hereditary angioedema is a rare and commonly misdiagnosed disease characterized by recurrent, painful, nonurticarial, and nonpruritic deep tissue swelling attacks, including potentially life-threatening asphyxiation. Nurses can assist in identifying disease hallmarks and provide emergency care, patient support, and education about injectable or infused medications.

Hereditary angioedema is a rare and commonly misdiagnosed disease. This article discusses how nurses can assist in identifying disease hallmarks and provide emergency care, patient support, and education.