The Panorama of Primary Angioedema in the Brazilian Population

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.

Complex analysis of the national Hereditary angioedema cohort in Slovakia - Identification of 12 novel variants in SERPING1 gene

Background

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disease characterised by acute episodes of non-pruritic skin and submucosal swelling caused by increase in vascular permeability.

Objective

Here we present the first complex analysis of the National HAE Slovakian cohort with the detection of 12 previously un-published genetic variants in SERPING1 gene.

Methods

In patients diagnosed with hereditary angioedema caused by deficiency or dysfunction of C1 inhibitor (C1-INH-HAE) based on clinical manifestation and complement measurements, SERPING1 gene was tested by DNA sequencing (Sanger sequencing/massive parallel sequencing) and/or multiplex ligation-dependent probe amplification for detection of large rearrangements.

Results

The Slovakian national cohort consisted of 132 living patients with confirmed HAE. We identified 51 index cases (32 families, 19 sporadic patients/112 adults, 20 children). One hundred seventeen patients had HAE caused by deficiency of C1 inhibitor (C1-INH-HAE-1) and 15 patients had HAE caused by dysfunction of C1 inhibitor (C1-INH-HAE-2). The prevalence of HAE in Slovakia has recently been calculated to 1:41 280 which is higher than average calculated prevalence. The estimated incidence was 1:1360 000. Molecular-genetic testing of the SERPING1 gene found 22 unique causal variants in 26 index cases, including 12 previously undescribed and unreported.

Conclusion

The first complex report about epidemiology and genetics of the Slovakian national HAE cohort expands the knowledge of the C1-INH-HAE genetics. Twelve novel causal variants were present in the half of the index cases. A higher percentage of inframe variants comparing to other studies was observed. Heterozygous deletion of exon 3 found in a large C1-INH-HAE-1 family probably causes the dysregulation of the splicing isoforms balance and leads to the decrease of full-length C1-INH level.

Universal Access to On-Demand Treatment of Patients with Hereditary Angioedema, the Chilean Experience

Background: In Chile, patients with hereditary angioedema (HAE) type I and type II are protected under Ley Ricarte Soto (LRS), which guarantees access to on demand plasma-derived C1-INH (pdC1-INH) since 2018. We aimed to analyze the first 3 years of LRS. Methods: Review of the LRS database between 2018 and 2021. Results: During the study period, 154 patients were covered by LRS, with an estimated prevalence of HAE in Chile at 0.8:100,000 inhabitants. A delay in diagnosis of 22 years was noted, 50 patients received epinephrine during an attack before the diagnosis of HAE. Mean number of attacks per year was 8, with 50% of adults and 42% of children experiencing more than 1 attack per month. Conclusion: Disease awareness must improve to reduce the diagnostic delay of HAE. Long-term prophylactic medications should be included in LRS to treat patients with high attack rates and control the costs of frequent on-demand treatment with pdC1-INH.

Patient-rated angioedema severity using a novel photo-aid for predicting non-mast cell mediator-induced angioedema diagnosis

Background

Patients with non-mast cell mediator-induced angioedema (NM-AE) usually experience a diagnostic delay. Therefore, a clinical tool for predicting NM-AE diagnosis is essential.

Objective

To identify clinical predictors related to a confirmed diagnosis of NM-AE.

Methods

Participants with a history of recurrent AE with unknown causes were enrolled. They were classified into mast cell mediator-induced AE (M-AE) and NM-AE according to the response to anti-mast cell mediator therapy. All participants were asked to rate their worst AE ever experienced (% Photomax) from 0 to 100% using a novel photo aid. Clinical characteristics were recorded and analyzed by univariable and multivariable analysis.

Results

Thirty-five participants were included, 25 with NM-AE and 10 with M-AE. AE located at extremities, face, and genitalia and positive family history were significantly associated with NM-AE. The AE severity in the NM-AE group was significantly higher than in the M-AE group, with the mean % Photomax of 82.4 ± 20.3 vs 47.5 ± 25.6 (p < 0.001), respectively. Univariable analysis showed that the % Photomax (every 10% increase), feet AE and hands AE were predictive of being NM-AE with the area under the receiver operating characteristic curve (AuROC) of 0.87 (95% CI 0.75, 0.99), 0.85 (95% CI 0.72, 0.98), and 0.84 (0.69, 0.99), respectively. Multivariable analysis showed that the combination of hands AE and % Photomax enhanced diagnostic accuracy (AuROC 0.94, 95% CI 0.86, 1.0) and constituted the prototype formula for calculating the diagnostic probability.

Conclusion

Patient-rated angioedema severity using a novel photo aid combined with hands AE had a high probability of diagnosing NM-AE.

Current challenges and future opportunities in patient-focused management of hereditary angioedema: A narrative review

Patients with hereditary angioedema (HAE) experience a high burden of disease due to unpredictable, painful, disfiguring, and potentially life-threatening HAE attacks. Multiple HAE-specific medications for the on-demand treatment, short-term and long-term prophylaxis of HAE attacks have entered the market in recent years; however, the availability and access to these medications may vary between different countries. For this review, PubMed and EMBASE databases were searched for guidelines, consensus statements, and other publications on HAE management as well as publications on quality of life in patients with HAE. The current guidelines and recent literature on HAE management in specific countries are summarized with the aim to highlight the similarities and differences between guideline recommendations and the country-specific clinical practice. Improvement in quality of life, which is a key goal in HAE management, is also discussed and the country-specific trends are highlighted. Finally, the ways to achieve a more patient-centric approach to HAE management within the framework set by the clinical management guidelines are examined.

Long-term Prophylaxis with Androgens in the management of Hereditary Angioedema (HAE) in emerging countries

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disease characterized by repetitive subcutaneous or submucosal angioedema, activation of the kinin system, and increased vascular permeability. C1-inhibitor (C1-INH) deficiency, the main mechanism of HAE pathogenesis, occurs when abnormal activation of plasma kallikrein, bradykinin, and factor XII, or mutation of genes such as SERPING1 cause quantitative or functional C1-INH defects. Although androgens are not approved for HAE treatment in many countries, they are widely used in China and Brazil to reduce the frequency and severity of HAE attacks. The long-term adverse effects of androgen treatment are concerning for both physicians and patients. Virilization, weight gain, acne, hirsutism, liver damage, headache, myalgia, hematuria, menstrual disorders, diminished libido, arterial hypertension, dyslipidemia, and anxiety/depression are commonly observed during long-term treatment with androgens. These adverse effects can affect the quality of life of HAE patients and often lead to treatment interruption, especially in women and children. In-depth studies of the pathogenesis of HAE have led to the approval of alternative treatment strategies, including plasma-derived C1 inhibitor, recombinant human C1 inhibitor, plasma Kallikrein inhibitor (ecallantide; lanadelumab), and bradykinin B2 receptor antagonist (icatibant), some of which have achieved satisfactory results with mostly non-serious side effects. Therefore, a new standard of medical care may expand possibilities for the management of HAE in emerging countries.

Mutation update of SERPING1 related to hereditary angioedema in the Chinese population

BACKGROUND

Hereditary angioedema (HAE) is a rare disease characterized by recurrent attacks of severe swellings of the skin and submucosa. More than 900 variants of the SERPING1 gene associated with HAE have been identified. However, only approximately 50 variants have been identified in the Chinese population. This study aimed to update the mutational spectrum in Chinese HAE patients and provide evidence for the accurate diagnosis of HAE.

METHODS

A total of 97 unrelated HAE patients were enrolled in the study. Sanger sequencing and multiple ligation-dependent probe amplification analysis were used to identify the variants in the SERPING1 gene. The variants were reviewed in a number of databases, including the Human Gene Mutation Database (HGMD) ( http://www.hgmd.cf.ac.uk/ ) and the Leiden Open Variation Database (LOVD, https://databases.lovd.nl/shared/variants/SERPING1 ). The American College of Medical Genetics and Genomics-Association for Molecular Pathology (ACMG-AMP) criteria was used to determine the pathogenicity of the variants.

RESULTS

Of the 97 patients, 76 different variants were identified in 90 of them and no disease-causing variants were identified in the remaining 7 patients. Among the 76 variants, 35 variants were novel and submitted to ClinVar. Missense and in-frame variants were the most common variants (36.8%), followed by frameshift (28.9%), nonsense (14.5%), splice site (13.2%) variants, and gross deletions/duplications (6.6%).

CONCLUSIONS

Our findings broaden the mutational spectrum of SERPING1 and provide evidence for accurate diagnosis and predictive genetic counseling.

SERPING1 Variants and C1-INH Biological Function: A Close Relationship With C1-INH-HAE

Hereditary angioedema with C1 Inhibitor deficiency (C1-INH-HAE) is caused by a constellation of variants of the SERPING1 gene (n = 809; 1,494 pedigrees), accounting for 86.8% of HAE families, showing a pronounced mutagenic liability of SERPING1 and pertaining to 5.6% de novo variants. C1-INH is the major control serpin of the kallikrein–kinin system (KKS). In addition, C1-INH controls complement C1 and plasminogen activation, both systems contributing to inflammation. Recognizing the failed control of C1s protease or KKS provides the diagnosis of C1-INH-HAE. SERPING1 variants usually behave in an autosomal-dominant character with an incomplete penetrance and a low prevalence. A great majority of variants (809/893; 90.5%) that were introduced into online database have been considered as pathogenic/likely pathogenic. Haploinsufficiency is a common feature in C1-INH-HAE where a dominant-negative variant product impacts the wild-type allele and renders it inactive. Small (36.2%) and large (8.3%) deletions/duplications are common, with exon 4 as the most affected one. Point substitutions with missense variants (32.2%) are of interest for the serpin structure–function relationship. Canonical splice sites can be affected by variants within introns and exons also (14.3%). For noncanonical sequences, exon skipping has been confirmed by splicing analyses of patients' blood-derived RNAs (n = 25). Exonic variants (n = 6) can affect exon splicing. Rare deep-intron variants (n = 6), putatively acting as pseudo-exon activating mutations, have been characterized as pathogenic. Some variants have been characterized as benign/likely benign/of uncertain significance (n = 74). This category includes some homozygous (n = 10) or compound heterozygous variants (n = 11). They are presenting with minor allele frequency (MAF) below 0.00002 (i.e., lower than C1-INH-HAE frequency), and may be quantitatively unable to cause haploinsufficiency. Rare benign variants could contribute as disease modifiers. Gonadal mosaicism in C1-INH-HAE is rare and must be distinguished from a de novo variant. Situations with paternal or maternal disomy have been recorded (n = 3). Genotypes must be interpreted with biological investigation fitting with C1-INH expression and typing. Any SERPING1 variant reminiscent of the dysfunctional phenotype of serpin with multimerization or latency should be identified as serpinopathy.

Angioedema Without Wheals: Challenges in Laboratorial Diagnosis

Angioedema is a prevailing symptom in different diseases, frequently occurring in the presence of urticaria. Recurrent angioedema without urticaria (AE) can be hereditary (HAE) and acquired (AAE), and several subtypes can be distinguished, although clinical presentation is quite similar in some of them. They present with subcutaneous and mucosal swellings, affecting extremities, face, genitals, bowels, and upper airways. AE is commonly misdiagnosed due to restricted access and availability of appropriate laboratorial tests. HAE with C1 inhibitor defect is associated with quantitative and/or functional deficiency. Although bradykinin-mediated disease results mainly from disturbance in the kallikrein–kinin system, traditionally complement evaluation has been used for diagnosis. Diagnosis is established by nephelometry, turbidimetry, or radial immunodiffusion for quantitative measurement of C1 inhibitor, and chromogenic assay or ELISA has been used for functional C1-INH analysis. Wrong handling of the samples can lead to misdiagnosis and, consequently, mistaken inappropriate approaches. Dried blood spot (DBS) tests have been used for decades in newborn screening for certain metabolic diseases, and there has been growing interest in their use for other congenital conditions. Recently, DBS is now proposed as an efficient tool to diagnose HAE with C1 inhibitor deficiency, and its use would improve the access to outbound areas and family members. Regarding HAE with normal C1 inhibitor, complement assays’ results are normal and the genetic sequencing of target genes, such as exon 9 of F12 and PLG, is the only available method. New methods to measure cleaved high-molecular-weight kininogen and activated plasma kallikrein have emerged as potential biochemical tests to identify bradykinin-mediated angioedema. Validated biomarkers of kallikrein–kinin system activation could be helpful in differentiating mechanisms of angioedema. Our aim is to focus on the capability to differentiate histaminergic AE from bradykinin-mediated AE. In addition, we will describe the challenges developing specific tests like direct bradykinin measurements. The need for quality tests to improve the diagnosis is well represented by the variability of results in functional assays.

Unnecessary Abdominal Surgeries in Attacks of Hereditary Angioedema with Normal C1 Inhibitor

Hereditary angioedema (HAE) is an autosomal dominant disease mostly due to the deficiency of C1 inhibitor (C1-INH). HAE with normal C1-INH was first described in 2000 and associated with mutations in the coagulation factor XII in 2006. Both diseases are associated with high bradykinin production, resulting in increased vascular permeability. Gastrointestinal edema due to HAE can be misdiagnosed as acute abdomen and unnecessary surgical procedures may be performed. The present study evaluates the prevalence of surgical procedures and/or acute abdomen in HAE patients with the coagulation factor XII mutation. It is a retrospective study where patients were diagnosed with recurrent angioedema without urticaria, normal C1-INH levels, and positive family history of angioedema. All patients were evaluated for the known mutations located at exon 9 of the F12 gene. Medical records were evaluated and questionnaires were applied to 52 patients with normal C1-INH levels (age range 13-76 years; 47/52, 90.38% women; 5/52, 9.61% men). F12 mutation was present in 32/52 patients (61.5%). Acute abdominal pain was diagnosed in 16/52 (30.76%) patients, appendicitis in 9/16 (56.2%), and undetermined diagnosis in 7/16 (43.7%). Among patients diagnosed with acute abdominal pain, 13/16 (81.2%) underwent surgery and 3/16 (18.7%) improved without surgical intervention. We conclude that many HAE patients with coagulation factor XII mutation were misdiagnosed with acute abdomen and subjected to unnecessary invasive procedures. It is critical to disseminate information about this rare mutation in patients with otherwise normal C1-INH activity, in order to speed up diagnosis and avoid misconduct.