Uncovering the true burden of hereditary angioedema due to C1-inhibitor deficiency: A focus on the Asia-Pacific region.

Hereditary angioedema (HAE) due to C1-inhibitor deficiency or dysfunction is a rare genetic disorder that causes recurrent episodes of swelling in various parts of the body. Treatment goals of HAE aim to "normalize" life for all patients; however, lack of diagnostic facilities and limited access to effective treatment options in developing nations cause delays in diagnosis and place a significant burden on patients. In this review, we aim to highlight the burden of disease caused by C1-inhibitor HAE across the Asia-Pacific region, considering its epidemiology, morbidity and mortality, and socioeconomic and psychological impact. We also review the availability of guideline-recommended diagnostic facilities and treatments, and how patients are currently managed. Data were collected from published literature and HAE experts in the region, who provided information regarding diagnosis and management in their countries. Current practice was reviewed against international guidelines, as well as local guidelines/consensus used in Australia, Japan, and China. Suggestions are provided for improving the time to diagnosis in the region, increasing access to guideline-recommended treatments, and providing support to reduce the burden on patients and caregivers. There is an urgent need to improve HAE services and provide access to life-saving treatment in developing countries, and efforts should be made to increase awareness of guideline recommendations in high-income economies that do not currently provide long-term prophylactic treatments.

Hereditary angioedema caused by a premature stop codon mutation in the SERPING1 gene.

BACKGROUND: Hereditary angioedema with deficient and dysfunctional C1 inhibitor (C1-INH-HAE) is a rare genetic disorder. The majority of the cases with this disease are caused by mutations in the C1-inbitor gene SERPING1 and are classified as type 1 and type 2. We aimed to detect mutations in the SERPING1 gene and evaluate its expression in nine probands with hereditary angioedema from nine different families. METHODS: Nine probands with hereditary angioedema from nine different families and 53 healthy controls were recruited in this study. All eight exons and intron-exon boundaries in the SERPING1 gene were amplified by PCR and then sequenced. Mutations were identified by alignment with reference sequences. mRNA expression was measured by real-time PCR. RESULTS: All probands were diagnosed with HAE type 1. Nine mutations were found in nine patients: c.44delT, c.289C

Upper airway edema in 43 patients with hereditary angioedema.

BACKGROUND: Upper airway edema (UAE) occurs infrequently in hereditary angioedema (HAE), but still results in significant morbidity and mortality. OBJECTIVE: To assess patients with HAE and UAE to determine whether unique features exist that can predict the risk of UAE. METHODS: Clinical, laboratory, and genetic data were compared between 43 patients with HAE and 743 UAE attacks and those without UAE and normal controls after ethics committee approval. RESULTS: Most patients had their first episode of UAE in the second (25.6%), third (27.9%), and fourth (23.3%) decades of life, and the mean age at onset was 27.3 years. Evolution of UAE from initial to maximum symptoms was 4.6 hours on average, and most cases (69.8%) progressed within 4 hours. Dyspnea was the most frequent manifestation in per-episode (92.2%) and per-patient (97.7%) analyses. Men developed more asphyxiation attacks (19 vs 2) and underwent more tracheotomies (12 vs 2) than did women. UAE was associated with facial edema in half the studied patients. Patients with a positive family history of UAE had a high risk of UAE attacks. CONCLUSION: Symptoms limited to the upper airway should be taken seriously. Dyspnea may be the only manifestation of UAE. UAE attacks most commonly start spontaneously and usually progress rapidly, as quickly as 30 minutes, from awareness of symptoms to maximum airway involvement. Patients with a positive UAE family history are predisposed to UAE attacks, and men appear to be more apt to develop asphyxiation than women.

Clinical features of hereditary angioedema in Chinese patients: new findings and differences from other populations.

BACKGROUND: Hereditary angioedema (HAE), caused by C1 inhibitor deficiency, is characterized by recurrent subcutaneous or submucosal swelling. Because it is rare, data on clinical features, especially in Chinese patients, are not comprehensive. OBJECTIVE: Our aim was to identify the characteristics of HAE in a Chinese population and enhance clinical knowledge of this disease. METHODS: One hundred and fifty-eight symptomatic patients were studied retrospectively. Data were obtained from medical records. Statistical analyses were performed using statistical software package: R version 2.14.0. RESULTS: The majority of patients first experienced attacks during the second (42%) and third (32%) decades: the mean onset of symptoms was at the age of 21.25 years. The percentage of patients having experienced a swelling at least once for the following sites were: extremities (83.54%); pharyngolarynx (58.86%); face (55.06%); gastrointestinal tract (34.17%); trunk (18.35%) and genitalia (15.33%). Rare manifestations included melaena, swollen gastric mucosa inverting into the oesophagus, pleural effusion, dysuria and syncope. For patients who first experienced swelling in pre-adolescence, 41.67% noted intensified attack rates when they entered puberty. In pregnancy, 61.70% did not note a change in HAE attack frequency. CONCLUSION: Compared with previous studies, the mean age of symptom onset is older. The frequencies of abdominal attacks occurring in patients on the Chinese Mainland, as well as in Taiwan and Japan, appears much lower than in western countries. Ethnic or environmental differences may contribute to this finding. Melaena and gastric mucosa inverting into the oesophagus secondary to edema are first reported here.

Recent advances in the management of hereditary angioedema.

Hereditary angioedema (HAE) is a rare genetic condition that manifests as painful and potentially life-threatening episodic attacks of cutaneous and submucosal swelling. It results from functional deficiency of C1 inhibitor (C1 INH), which is a regulator of the complement, fibrinolytic, kinin (contact), and coagulation systems. In patients with HAE, the low plasma concentration of functional C1 INH leads to overactivation of the kinin cascade and local release of bradykinin. Bradykinin is responsible for the pain, vascular permeability changes, and edema associated with HAE. Until recently, therapeutic options for HAE have been very limited. Many new therapies have emerged, however, such as C1 INH replacement drugs and medications aimed at components of the contact system (eg, plasma kallikrein inhibitor and bradykinin B2 receptor antagonist). The authors review current and novel treatments for patients with HAE.

Comparison and evaluation of several Dermatophagoides pteronyssinus allergen extracts for skin prick test.

OBJECTIVE: To evaluate the significance of several Dermatophagoides pteronyssinus allergen extracts for skin prick test (SPT) in patients allergic to Dermatophagoides pteronyssinus. METHODS: Two hundred and nineteen patients enrolled in Peking Union Medical College Hospital underwent SPT and serum specific IgE assay to detect the Dermatophagoides pteronyssinus allergen. Three kinds of house dust mite allergen extracts were used for SPT, including the Dermatophagoides pteronyssinus extract prepared by our laboratory (group A), standardized Dermatophagoides pteronyssinus extract (group B), and mixed extracts of Dermatophagoides pteronyssinus and Dermatophagoides farinae (group C). Human serum specific IgE result was regarded as the reference standard for diagnosis of Dermatophagoides pteronyssinus allergy. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performance of SPT with the extracts of three groups. RESULTS: SPT results showed that the median wheal diameter of group A, group B, and group C was 0.43, 0.35, and 0.28 cm, respectively, with significant difference among three groups (P<0.05). The difference was significant between group A and B (P<0.01) as well as group A and C (P<0.01), but not between group B and C (P>0.05). There was no local urticaria or systemic allergic reactions following the procedure of SPT. Local reaction was observed in 5 patients and delayed reaction was in 2 patients of group A. As for group B and C, local reaction occurred in 3 cases and delayed reaction in 2 cases in each group. The area under ROC curve of SPT with extract in group A, group B, and group C was 0.765, 0.801, and 0.782, respectively. Based on the detection results of serum specific IgE, the sensitivity of SPT in diagnosis of Dermatophagoides pteronyssinus allergy with extract of group A, group B, and group C was 92.4%, 87.0%, and 81.5%, and the specificity was 60.6%, 73.2%, and 74.8%, respectively. CONCLUSION: The Dermatophagoides pteronyssinus extract for SPT prepared by our laboratory offers good sensitivity and specificity comparable to commercially available allergen extracts, and it may be an appropriate candidate for clinical screening and diagnosis of Dermatophagoides pteronyssinus allergy.

[Identification of a novel mutation of C1 inhibitor gene in a Chinese family with hereditary angioedema].

OBJECTIVE: To identify the mutation of C1 inhibitor (C1 INH) gene in a Chinese family with hereditary angioedema (HAE). METHODS: Polymerase chain reaction and direct sequencing were used to identify the mutation type. The sequencing results were compared with the normal sequences in GenBank to find the mutation. In order to exclude the polymorphism, 30 normal volunteers were analyzed. RESULTS: One novel mutation (17839 del C) was detected in 5 patients with HAE. The mutation was not found in controls. CONCLUSION: The mutation of C1 INH gene (17839 del C) is identified in the family. Molecular diagnosis can be made by detecting the mutation.