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.

Hereditary Angioedema Type 1 and 2 in Finland: Incidence, Prevalence, and Preceding Diagnoses

Abstract is missing (Short communication)

Acquired complement C1 esterase inhibitor deficiency in a patient with a rare SERPING1 variant with unknown significance

Angioedema (AE) is caused by a wide range of diseases and pharmaceuticals; it can become life-threatening when located to the airways. Patients with deficiency or malfunction of complement C1 esterase inhibitor (hereditary or acquired) experience recurrent AE due to an accumulation of the vasoactive mediator bradykinin (BK). Complement C1 inhibitor normally decreases BK production, so a reduced function hereof causes increased levels. The diagnosis of hereditary or acquired AE can be difficult due to similarities to allergic reactions (swelling, abdominal pain, rash). We describe a 35-year-old man presenting with upper-airway AE progressing rapidly and promptly required cricothyroidotomy. Complement and autoantibody screening together with sequencing of SERPING1 were performed and gave the diagnosis of acquired complement C1 esterase inhibitor deficiency. The patient is unusual to have this disease before the age of 40 years. No associated comorbidities were found. It is important to know that antiallergic medication is not effective in BK-mediated AE.

Hereditary Angioedema Type 1 with Recurrent Dizziness

A 41-year-old woman presented with recurrent dizziness. After an attack of dizziness, she felt edematous sensations in her hands. However, according to photographs taken during the attack, the edema on the back of the patient's hands and fingers appeared mild. Laboratory examinations revealed a low C4 and C1 inhibitor (INH) activity. A direct sequencing analysis of C1INH revealed a pathogenic gene mutation. Based on these results, she was diagnosed with hereditary angioedema (HAE) type 1. These findings indicate that HAE can cause recurrent dizziness, and it should therefore be included in the differential diagnosis in patients with recurrent neurologic symptoms, even in the absence of severe edema.

Hereditary angioedema: 44 years of diagnostic delay

We report a 64-year-old man who suffered from recurrent visible swelling attacks since the age of 20 as well as episodes with severe upper airway edema, resulting in 4 emergency tracheotomies. Eventually after 44 years he was diagnosed with hereditary angioedema (HAE) type II. The aims of this report is to emphasize the importance of awareness concerning HAE, which does not respond to traditional anti-allergic therapy, and remind physicians to test for functional C1-INH deficiency.

Hereditary Angioedema with Recurrent Abdominal Pain in a Patient with a Novel Mutation

We describe a patient with hereditary angioedema type I. The patient had experienced recurrent abdominal pain around the time of her menstrual period for 13 years. A laboratory examination showed reduced functional and antigenic levels of C4 and C1 inhibitor (C1-INH). To establish a diagnosis, we carried out a DNA analysis of the patient's C1-INH gene. We determined that the patient was heterozygous for a single base pair transposition of T to C at nucleotide 4429 in exon 4, which had not been reported in the literature. As the patient had no family history of hereditary diseases, it was considered to be a de novo mutation.

[Hereditary angioedema: strange cause of abdominal pain]

BACKGROUND

Hereditary angioedema is an episodic swelling disorder with autosomal dominant inheritance characterized by sudden attacks of peripheral swelling. Patients also commonly have episodic swelling of the wall of hollow viscera, including the bowel.

CLINICAL CASE

We present a 33-year-old previously healthy male with a complaint of acute-onset intense abdominal pain localized in the epigastrium. Pain irradiated to the right lower quadrant and was associated with five episodes of vomiting. Computed tomography showed thickening of the duodenal wall with liquid in the subphrenic space. Complementary laboratory tests showed low C4 complement levels (5.5 mg/dl) and 30% complement C1 inhibitor activity.

CONCLUSIONS

Hereditary angioedema is caused by a deficiency (type I) or dysfunction (type II) in complement C1 inhibitor. Abdominal associated with angioedema may manifest as severe acute-onset abdominal pain or as moderately severe chronic recurrent abdominal pain. Two medications are currently FDA-approved for the treatment of these patients.

Overview of hereditary angioedema caused by C1-inhibitor deficiency: assessment and clinical management

Hereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) is a rare, autosomal-dominant disease. HAE-C1-INH is characterized by recurrent attacks of marked, diffuse, nonpitting and nonpruritic skin swellings, painful abdominal attacks, and laryngeal edema. The extremities and the gastrointestinal tract are most commonly affected. Swelling of the upper respiratory mucosa poses the greatest risk because death from asphyxiation can result from laryngealedema. HAE-C1-INH attacks are variable, unpredictable, and may be induced by a variety of stimuli, including stress or physical trauma. Because the clinical presentation of HAE-C1-INH is similar to other types of angioedema, the condition may be a challenge to diagnose. Accurate identification of HAE-C1-INH is critical in order to avoid asphyxiation by laryngeal edema and to improve the burden of disease. Based on an understanding of the underlying pathophysiology of IHAE-C1-INH, drugs targeted specifically to the disease, such as C1-inhibitor therapy, bradykinin B2-receptor antagonists, and kallikrein-inhibitors, have become available for both treatment and prevention of angioedema attacks. This article reviews the clinical features, differential diagnosis, and current approaches to management of HAE-C1-INH.

A novel mutation in exon 8 of C1 inhibitor (C1INH) gene leads to abolish its physiological stop codon in a large Chinese family with hereditary angioedema type I

C1 inhibitor (C1INH) plays an important role in the classical pathway of the complement system. Mutations in C1INH gene cause quantitative or qualitative deficiencies in C1INH, which can lead to hereditary angioedema (HAE) type I or II. Here, we identified a novel frame-shift mutation c.1391-1445del55 (p.v464fsx556) in exon 8 in a large Chinese family with HAE type I. This 55 base pairs deletion abolishes the original stop codon and introduces a new stop codon 220 bp downstream of the original one, and leads to mutated C1INH protein prolonged from 500 to 556 amino acids. The levels of C4 and C1INH as well as C1INH activity in serum were significantly reduced in affected individuals. This is the first report of a novel mutation abolishing the physiological stop codon of C1INH gene in a large Chinese family with HAE type I.

Hereditary and acquired complement component 1 esterase inhibitor deficiency: a review for the hematologist

Hereditary angioedema (HAE), a rare autosomal dominant disorder, was first described in the late 19th century. The disease remained poorly understood and without therapeutic options until the latter half of the 20th century. Advances in the understanding of immunologic and hematologic pathways have shed light on HAE, a disease characterized by painful and unpredictable recurrent attacks of nonpitting edema without urticaria. Recognition that a deficiency of complement component 1 (C1) esterase inhibitor leads to overproduction of vasoactive kinins that cause angioedema paved the way for the development of early treatments. Increased understanding of the role of bradykinin in hereditary and acquired forms of C1 esterase inhibitor deficiency has led to the development of more targeted treatments for this painful, debilitating and potentially life-threatening disease.

Type I hereditary angioedema in Taiwan -- clinical, biological features and genetic study

BACKGROUND

Hereditary angioedema (HAE) is a rare, autosomal dominant inherited disease which is caused by a genetic deficiency of C1 esterase inhibitor (C1 INH). There have only been a few case reports in Taiwan to date.

OBJECTIVE

To describe the clinical features of type I HAE in Taiwanese patients.

METHODS

Three unrelated Taiwanese families with type I HAE are reported, and one case of a family from a review of PubMed was reviewed. Clinical manifestations, diagnostic examinations, management and genetic studies were analyzed.

RESULTS

Including this report, 19 patients had low C1 INH and low C4 levels and were diagnosed with type I HAE. Only 11 (57.9%) patients were symptomatic. Recurrent skin swelling and edema over the four extremities or trunk were reported in all symptomatic patients (100%). 45.5% of the patients recalled laryngeal attacks and one patient died from asphyxia. 18.2% of the patients experienced abdominal symptoms. The age at the beginning of clinical symptoms ranged from 5 to 30 years (mean +/- SD: 20.82 +/- 7.88 years). The diagnosis tended to be delayed (range from 1 to 39 years; mean +/- SD: 8.45 +/- 11.04 years). Nine patients had a mutant C1 INH gene, and two patients received long-term prophylaxis with danazol.

CONCLUSION

The prevalence of hereditary angioedema in Taiwan is low. Persons with low levels of C1 INH who were clinically symptomatic accounted for only 57.9% of the cases in our study, which is far lower than previous reports from other countries. Ethnic differences may be the reason for this finding. Further genomic studies are needed to elucidate the genetic penetrance of C1 INH deficiency in Taiwan.

A case of hereditary angioedema involving recurrent abdominal attacks

A 44-year-old Japanese woman was diagnosed with type 1 hereditary angioedema (HAE) at the age of 30. In March 2007, she began suffering from severe abdominal pain due to intestinal edema. After treatment with C1-INH concentrate, her symptoms disappeared. However, during the subsequent three years, the frequency of the attacks increased continuously, and C1-INH concentrate was necessary for treatment of every attack. The increase in the number of attacks might have been due to the frequent injection of C1-INH concentrate or the deterioration of her disease course. In a genetic investigation, the patient was found to have a novel mutation in the C1-INH gene.

[Hereditary angioedema. Family history and clinical manifestations in 58 patients]

Hereditary angioedema (HAE) is a rare autosomal dominant disease, characterized by episodes of edema typically involving the skin, gastrointestinal tract and larynx. We here describe the epidemiologic and clinical characteristic of a series of 58 patients with diagnosis of HAE, 53 (91%) type I and 5 (9%) type II. The mean age at first symptom was 10.8 +/- 9.5 years and the mean age at diagnosis was 25.8 +/- 16.2 years old, with a diagnosis delay of 15.3 +/- 14.3 years. The mean number of attacks in the previous 6 months was 7.4 +/- 7.6 range 0 to 40. Fifty four (93%) had cutaneous attacks, 50 (86%) abdominal attacks, 24 (41%) laryngeal attacks and 24 (41%) combined cutaneous and abdominal attacks. Twenty seven (46.5%) patients never received preventive treatments and 17 (29%) received danazol in different doses for different periods of time. During the attacks, 15 (26%) patients were treated with C1 inhibitor at least once, 7 (12%) with fresh frozen plasma and 40 (69%) received only supportive treatment. Stress and trauma were identified as attacks triggers. Six (10%) patients were first mutation and 52 (90%) had HAE ancestors. We reconstructed 20 kindred, identifying 205 individuals at risk of inheriting the disease, 109 (53 %) of them had signs or laboratory diagnosis of HAE. The total number of identified HAE individuals was 145, 19 (13%) died with asphyxia. So, shortening of diagnosis delay and appropriate treatment of HAE are a challenge to be fulfilled.