Missense mutation Thr309Lys in the coagulation factor XII gene in a Spanish family with hereditary angioedema type III

Leveraging Genetics for Hereditary Angioedema: A Road Map to Precision Medicine

Biochemical studies performed during the last decades resulted in the development of various innovative medicinal products for hereditary angioedema (HAE). These therapeutic agents target the production or the function of bradykinin-the main mediator of HAE due to C1-inhibitor (C1-INH) deficiency. However, despite these remarkable achievements, current knowledge cannot provide convincing explanations for the clinical variability of the disease. As a consequence, treatment indications apply for drugs available for C1-INH deficiency. The advent of high-throughput next-generation sequencing technologies may assist in covering the missing part of our understanding of HAE pathogenesis. During the last 3 years alone, several new entities were added to the already described genotypes. The recent discovery of four novel target genes expands our understanding of other causes which may explain recurrent angioedema in individuals and families with normal C1-INH activity. Furthermore, new genetic technologies allowed the recognition of deep intronic variants associated with the disease, and elegant functional studies characterized new variants for the C1-INH gene. Thus, evidence has been provided regarding pathogenetic aspects remaining obscure for many years, such as the defective intracellular transport of mutant C1-INH, and environmental effect on the disease expression. Therefore, it seems that the stage for Precision Medicine era in HAE management is ready. Disease endotypes are expected to be uncovered and specified targets for therapeutic intervention will be detected, promising a more effective, individualized management of the disease.

Clinical features of genetically characterized types of hereditary angioedema with normal C1 inhibitor: a systematic review of qualitative evidence

BACKGROUND

Hereditary angioedema (HAE) with normal C1 inhibitor (C1-INH) (HAEnCI) is associated with skin swellings, abdominal attacks, and the risk of asphyxia due to upper airway obstruction. Several different gene mutations linked to the HAE phenotype have been identified. Our aim was to qualitatively assess and describe the clinical differentiators of these genetically identified HAEnCI types. To achieve this, we performed a systematic literature review of patients with angioedema symptoms and a genetically confirmed diagnosis of an HAEnCI type.

RESULTS

A systematic literature search, conducted in March 2020, returned 132 records, 43 of which describe patients with symptoms of angioedema and a genetically confirmed diagnosis of an HAEnCI type. Overall, this included 602 patient cases from 220 families. HAEnCI with a mutation in the coagulation factor XII gene (F12) (HAE-FXII) was diagnosed in 446 patients from 185 families (male:female ratio = 1:10). Estrogens (oral contraceptives, hormonal replacement therapy, and pregnancy) negatively impacted the course of disease in most female patients (252 of 277). Asphyxia occurred in 2 of 446 patients. On-demand and/or long-term prophylaxis treatment included C1-INH concentrates, icatibant, progestins, and tranexamic acid. HAEnCI with a specific mutation in the plasminogen gene (HAE-PLG) was diagnosed in 146 patients from 33 families (male:female ratio = 1:3). Estrogens had a negative influence on the course of disease in the minority of female patients (14 of 62). Tongue swelling was an important clinical feature. Asphyxia occurred in 3 of 146 patients. On-demand treatment with icatibant and C1-INH concentrate and long-term prophylaxis with progestins and tranexamic acid were effective. HAEnCI with a specific mutation in the angiopoietin-1 gene (HAE-ANGPT1) was diagnosed in 4 patients from 1 family and HAEnCI with a specific mutation in the kininogen-1 gene (HAE-KNG1) in 6 patients from 1 family.

CONCLUSIONS

A number of clinical differentiators for the different types of HAEnCI have been identified which may support clinicians to narrow down the correct diagnosis of HAEnCI prior to genetic testing and thereby guide appropriate treatment and management decisions. However, confirmation of the causative gene mutation by genetic testing will always be required.

Wolf in the sheep's clothing: intestinal angioedema mimicking infectious colitis

Hereditary angioedema (HAE) is a relatively rare clinical entity that can potentially cause life-threatening airway or intestinal oedema, patients with the latter usually presents with symptoms of gastroenteritis like vomiting, diarrhoea and abdominal pain. Here, we present a unique case of a less recognised type of HAE that is type III in a patient who presented with signs and symptoms consistent with infectious colitis. She previously had similar episodes and was managed multiple times with antibiotics, with no satisfactory response. There, she underwent extensive diagnostic evaluation. On the basis of findings of further investigations on the current visit, she was eventually diagnosed with intestinal angioedema. To the best of our knowledge, the present paper represents the third reported case of type III HAE-induced intestinal angioedema. Additionally, we undertake a literature review of HAE.

Clinical Utility Gene Card for hereditary angioedema with normal C1 inhibitor (HAEnC1)

1. Name of the disease (synonyms)

Hereditary angioedema type III (HAE-III)

Estrogen-related hereditary angioedema

Hereditary angioedema with factor XII mutations (FXII-HAE)

Hereditary angioedema of unknown origin (U-HAE)

2. OMIM# of the disease

610618

3. Name of the analysed genes or DNA/chromosome segments:

Coagulation factor XII; Hageman factor; F12; chromosome 5q.35.2-q35.3

4. OMIM# of the gene(s)

610619

Review of the analytical and clinical validity as well as of the clinical utility of DNA-based testing for mutations in the F12 gene(s) in ⊠ diagnostic, ⊠ predictive and ⊠ prenatal settings and for, ⊠ risk assessment in relatives.

Hereditary angioedema with normal C1 inhibitor and factor XII mutation: a series of 57 patients from the French National Center of Reference for Angioedema

Hereditary angioedema (HAE) is a rare disease associated with either a quantitative or qualitative deficiency in C1-inhibitor (C1-INH) or normal C1-INH. HAE with normal C1-INH is associated in 20% of cases with mutations in the gene for factor XII (FXII) or FXII-HAE. A recent review described 41 families, including 14 German and 15 Spanish families. We have constructed a register of French patients and their characteristics. A national survey was launched through the French National Center of Reference for Angioedema (CREAK) to study the clinical, biological and therapeutic characteristics of patients with HAE linked to a mutation of FXII gene. Fifty-seven patients were identified from 24 different families. In most cases they were young women (mean age at diagnosis: 31 years, mean age at first symptom: 21 years, female/male ratio: 76%). Twenty-one per cent of the patients experienced angioedema attacks only during pregnancy or when on oestrogen contraception. Sixty-three per cent had attacks at all times, but they were more severe during these same periods. Male carriers of the mutation were more frequently asymptomatic than females (P = 0·003). C1-INH concentrate and icatibant were both effective for treating attacks. The prophylactic use of tranexamic acid led to a 64% decrease in the number of attacks. This is one of the largest series reported of HAE patients with FXII mutation. The therapeutic management appeared to be identical to that of HAE with C1-INH deficiency.

Hereditary angioedema with F12 mutation: Clinical features and enzyme polymorphisms in 9 Southwestern Spanish families

BACKGROUND

Information on F12 mutation hereditary angioedema (HAE) is still limited, but Spain is now recognized as having one of the highest concentrations of cases in Western Europe.

OBJECTIVE

To describe unique features of HAE in Spanish carriers of the F12 mutation and investigate a potential role for angiotensin-converting enzyme (ACE) and aminopeptidase-P polymorphisms in disease expression.

METHODS

This was a prospective observational cohort study of 35 individuals (80% females) from 9 unrelated families carrying the p.Thr309Lys mutation. We analyzed detailed medical records and complement activity (C4, C1q, C1 inhibitor) and screened for mutations in exon 9 of the F12 gene and 2 polymorphisms: XPNPEP2 c-2399A and the ACE insertion/deletion polymorphism.

RESULTS

The p.Thr309Lys mutation was found in all individuals. Three of the 9 index patients had a clinically negative family history, and 72% of males and 29% of females were asymptomatic. Sixteen females (44% estrogen dependent, 56% estrogen sensitive) were clearly symptomatic. The most common locations of attacks were the abdomen (63%), face (25%), and peripheral structures (6%). Triggers other than hyperestrogenic states included stress and minor trauma or pressure. Short-term treatment with C1-inhibitor concentrate and icatibant and long-term prophylaxis with tranexamic acid were useful. The combination of the I allele and A allele was detected in 17% of patients.

CONCLUSION

The polymorphisms analyzed were not a major determinant of disease expression in our population. We recommend searching for F12 mutations in women with edema attacks without associated wheals and with normal C1-inhibitor levels, particularly when they develop symptoms during hyperestrogenic states or are of Western European or African origin.

Homozygosity for a factor XII mutation in one female and one male patient with hereditary angio-oedema

Hereditary angio-oedema (HAE) with normal C1 inhibitor is associated with heterozygous mutations in the factor XII gene (FXII-HAE). We report two Brazilian FXII-HAE families segregating the mutation c.983 C>A (p.Thr328Lys). In each family, one patient with a homozygous mutation was found. The homozygous female patient in family 1 displayed a severe phenotype. However, this falls within the clinical phenotype spectrum reported for heterozygous female mutation carriers. The homozygous male patient in family 2 also showed a severe phenotype. This finding is intriguing, as to our knowledge, it is the first such report for a male FXII-HAE mutation carrier. In the rare instances in which male mutation carriers are affected, a mild phenotype is typical. The present findings therefore suggest that homozygous FXII-HAE mutation status leads to a severe phenotype in females and males, and to an increased risk of manifest symptoms in the latter.

Characterization of patients with angioedema without wheals: the importance of F12 gene screening

Sporadic and familiar forms of non-histaminergic angioedema and normal C1 inhibitor encompass a group of disorders possibly caused by bradikinin. We aimed to study the subgroups of hereditary angioedema with FXII mutation (FXII-HAE), unknown genetic defect (U-HAE) and idiopathic non-histaminergic acquired angioedema (InH-AAE). We screened the F12 locus in our cohort and delineated the clinical, laboratory and genetic features. Four families carried the p.Thr309Lys mutation in F12 gene. Haplotyping confirmed the hypothesis of a common founder. Six families were affected by U-HAE and 13 patients by sporadic InH-AAE. C4 levels were significantly lower in FXII-HAE than in InH-AAE. In the FXII-HAE group, none had attacks exclusively in high estrogenic states; acute attacks were treated with icatibant. Prophylaxis with tranexamic acid reduced the attack frequency in most patients. Our study provides new data on the diagnosis, clinical features and treatment of non-histaminergic angioedema, underlying the role of the screening for F12 mutations.

Hereditary angioedema: a brief review of new developments

BACKGROUND

Angioedema is a serious medical condition characterized by recurrent non-pitting tissue edema. Hereditary (HAE) forms of this disorder are potentially fatal.

METHODS

PubMED, Up to Date and Cochrane Library databases were used to identify scholarly peer reviewed original research or review articles on angioedema. Search terms used were: angioedema, HAE, ACE inhibitor induced angioedema, acquired angioedema, type III HAE (now termed HAE with normal C1-INH), diagnosis of HAE, and treatment of HAE. Inclusive dates of the search were 1946 through 2013. Articles on urticaria were excluded.

RESULTS

The pathophysiology, clinical manifestations, differential diagnosis and treatments of angioedema are presented. Three variants of HAE are discussed and differentiated from acquired, ACE induced and allergic types of angioedema. Emphasis is placed on understanding that HAE is mediated by bradykinin, not histamine, and is therefore unresponsive to antihistamines, corticosteroids and epinephrine. In contrast, newer therapies that replace C1-INH or block bradykinin production or action are the appropriate treatments for prophylaxis and acute treatment of HAE.

CONCLUSION

Recognition of HAE by primary care providers and distinguishing it from allergic histamine mediated angioedema is essential in preventing recurrent attacks and avoiding inappropriate therapy, and may be life-saving.

Angioedema with normal laboratory values: the next step

When faced with a patient with recurrent swelling, a thorough laboratory evaluation to determine the underlying etiology ensues. When the laboratory work-up is unrevealing, health care practitioners are frequently left in a quandary. This review will attempt to provide up-to-date information on how to approach the diagnosis and management of angioedema in a patient with normal laboratory values. The subtypes that will be reviewed in detail include: hereditary angioedema with normal C1 inhibitor (HAE with normal C1INH), drug-induced angioedema, and idiopathic angioedema. We present literature to aid the physician in the diagnosis and treatment of these disorders.

Hereditary angioedema with normal C1 inhibitor

Until recently it was assumed that hereditary angioedema was a disease that results exclusively from a genetic deficiency of the C1 inhibitor. In 2000, families with hereditary angioedema, normal C1 inhibitor activity, and protein in plasma were described. Since then, numerous patients and families with that condition have been reported. Most of the patients were women. In many of the affected women, oral contraceptives, hormone replacement therapy containing estrogens, and pregnancies triggered the clinical symptoms. In some families mutations in the coagulation factor XII (Hageman factor) gene were detected.

Clinical, biochemical, and genetic characterization of type III hereditary angioedema in 13 Northwest Spanish families

BACKGROUND

A new variant of hereditary angioedema has been reported during the last decade. Three main characteristics distinguish it from classic hereditary angioedema: normal C1 inhibitor activity, predominance in women, and different genetic alterations.

OBJECTIVE

To assess the symptoms, laboratory findings, and treatment of a population with type III hereditary angioedema from Northwest Spain.

METHODS

We studied 29 patients (26 female and 3 male) from 13 different families.

RESULTS

The 26 female patients showed a similar clinical pattern to the classic forms of hereditary angioedema, and 22 of these patients had the estrogen-dependent phenotype. Three patients had a negative family history, and 1 of the parents was confirmed as an asymptomatic carrier in 2 of them. All had functional C1 inhibitor activity within the normal range in periods without high estrogen levels, but during attacks (in female patients) and pregnancy, activity decreased to below 50%. One male patient had normal C1 inhibitor activity during attacks, and he was initially diagnosed as having idiopathic angioedema. The C4 and antigenic C1 inhibitor levels were always normal. All studied patients had the c.1032C>A, Thr309Lys mutation in the factor XII gene. The mutation was also found in asymptomatic relatives: 5 of 6 men studied and 1 of 8 women studied.

CONCLUSION

Positive family history is a diagnosis criterion, but it could be lacking because there may be asymptomatic relatives, primarily males.

A single nucleotide deletion at the C1 inhibitor gene as the cause of hereditary angioedema: insights from a Brazilian family

BACKGROUND

Hereditary angioedema is an autosomal dominant disease characterized by episodes of subcutaneous and submucosal edema. It is caused by deficiency of the C1 inhibitor protein, leading to elevated levels of bradykinin. More than 200 mutations in C1 inhibitor gene have been reported. The aim of this study was to analyze clinical features of a large family with an index case of hereditary angioedema and to determine the disease-causing mutation in this family.

METHODS

Family pedigree was constructed with 275 individuals distributed in five generations. One hundred and sixty-five subjects were interviewed and investigated for mutation at the C1 inhibitor gene. Subjects reporting a history of recurrent episodes of angioedema and/or abdominal pain attacks underwent evaluation for hereditary angioedema.

RESULTS

We have identified a novel mutation at the C1 inhibitor gene, c.351delC, which is a single-nucleotide deletion of a cytosine on exon 3, resulting in frameshift with premature stop codon. Sequencing analysis of the hypothetical truncated C1 inhibitor protein allowed us to conclude that, if transcription occurs, this protein has no biological activity. Twenty-eight members of the family fulfilled diagnostic criteria for hereditary angioedema and all of them presented the c.351delC mutation. Variation in clinical presentation and severity of disease was observed among these patients. One hundred and thirty-seven subjects without hereditary angioedema did not have the c.351delC mutation.

CONCLUSION

The present study provides definitive evidence to link a novel genetic mutation to the development of hereditary angioedema in patients from a Brazilian family.

Type III hereditary angio-oedema: clinical and biological features in a French cohort

BACKGROUND

Hereditary angio-oedema (HAE) has been associated with C1inhibitor deficiency. The first cases of type III HAE were described in patients with normal C1Inh antigenic protein level and function and normal C4 levels in 2000. This finding has been reported mostly in women with a family history and may be influenced by exogenous oestrogen exposure.

OBJECTIVES

The purpose of this article is to describe the clinical, biological and genetic characteristics of a French population suffering from type III HAE.

PATIENTS AND METHODS

We conducted a retrospective analysis of angio-oedema (AE) cases seen in the National Reference Centre of AE between 2000 and 2009.

RESULTS

We found 26 patients (from 15 unrelated families) with type III HAE. All but four were women and presented with typical AE attacks, exacerbated by pregnancy or oral contraceptives containing oestrogens (OC). We also found that 54.5% of women were worsened with oestrogen and 23% were oestrogen dependent. All patients improved on long-term prophylactic tranexamic acid treatment; some acute attacks improved with C1Inh concentrate infusion. All of the patients had normal C1Inh and C4 levels. C1Inh function was also normal, except in women receiving OC or during a pregnancy: transient, moderately low levels (32-74% of the normal range) were found in 18 patients tested (67%). No SERPING1 gene mutation was found. Six patients from three unrelated families were heterozygous for an F12 gene variant.

CONCLUSION

Diagnosis of type III HAE should be based on clinical (typical attacks, often hormonally influenced), laboratory (normal C1Inh antigenic protein) and genetic (F12 gene mutation) evidence.

Diagnosis and treatment of hereditary angioedema with normal C1 inhibitor

Until recently it was assumed that hereditary angioedema is a disease that results exclusively from a genetic deficiency of the C1 inhibitor. In 2000, families with hereditary angioedema, normal C1 inhibitor activity and protein in plasma were described. Since then numerous patients and families with that condition have been reported. Most of the patients by far were women. In many of the affected women, oral contraceptives, hormone replacement therapy containing estrogens, and pregnancies triggered the clinical symptoms. Recently, in some families mutations in the coagulation factor XII (Hageman factor) gene were detected in the affected persons.