G. Witzke

Long-term prophylaxis with C1-inhibitor (C1 INH) concentrate in patients with recurrent angioedema caused by hereditary and acquired C1-inhibitor deficiency☆

A case of hereditary angioedema (HAE) type I (inherited C1-inhibitor [C1 INH] deficiency) and a case of late-onset acquired C1 INH with angioedema is described. In both patients, long-term prophylaxis with C1 INH had become necessary because treatment with danazol and epsilon-aminocaproic acid was not effective or not tolerated. Consequently, both patients received a pasteurized concentrate of C1 INH continuously for a period of 1 year in a dosage that kept them free of symptoms. The patient with HAE was administered 500 units of C1 INH intravenously every 4 or 5 days, whereas the patient with acquired angioedema required 1000 units of C1 INH every 5 days. As a result of this long-term prophylaxis, both patients became free or nearly free from their episodes of cutaneous and internal edema. The low plasma levels of C1 INH, C4, and C2, rose. In the patient with acquired C1 INH deficiency, the swellings increasingly reappeared after 10 months, although the patients antibody titer did not rise during treatment. No side effects were recorded during therapy. In particular, both patients remained HIV and hepatitis B antibody negative.

Hereditary angioedema caused by missense mutations in the factor XII gene: Clinical features, trigger factors, and therapy

BACKGROUND Hereditary angioedema caused by mutations in the factor XII gene is a recently described disease entity that occurs mainly in women. It differs from hereditary angioedema caused by C1 inhibitor deficiency. OBJECTIVE To assess the clinical symptoms, factors triggering acute attacks, and treatments of this disease. METHODS Thirty-five female patients with hereditary angioedema and the factor XII mutations p.Thr309Lys and p.Thr309Arg who came from 13 unrelated families were studied. The observation period was 8.4 years on average (range, 2-26 years). RESULTS Patients had on average 12.7 +/- 7.9 angioedema attacks per year. Recurrent facial swellings occurred in all patients; skin swellings other than facial, abdominal pain attacks, tongue swellings, and laryngeal edema occurred less frequently. Some factors that triggered angioedema attacks were trauma, physical pressure, and emotional stress. Clinical symptoms started mainly after intake of oral contraceptives (17 women) or pregnancy (3 women). Exacerbation of the symptoms occurred after oral contraceptive use (8 women), pregnancy (7 women), hormone replacement therapy (3 women), intake of angiotensin-converting enzyme inhibitors (2 women), and an angiotensin 1 receptor blocker (1 woman). Effective treatments included C1 inhibitor concentrate for angioedema attacks (6 women) and, for prophylaxis, progesterone (8 women), danazol (2 women), and tranexamic acid (1 woman). No difference between mutation p.Thr309Arg and p.Thr309Lys was found. CONCLUSIONS Facial swelling is a cardinal symptom of this condition. Estrogens may have a great influence, but this influence is highly variable. Various treatment options are available.

A novel mutation in the coagulation factor 12 gene in subjects with hereditary angioedema and normal C1-inhibitor.

In hereditary angioedema with normal C1-inhibitor two different missense mutations of codon p.Thr328* in the coagulation factor 12 gene have been reported in some families. In this study a novel factor 12 gene mutation, the deletion of 72 base pairs (bp) (c.971_1018+24del72*), was identified in a family of Turkish origin, in two sisters with recurrent skin swellings and abdominal pain attacks and in their symptom-free father. This deletion caused a loss of 48 bp of exon 9 (coding amino acids 324* to 340*) in addition to 24 bp of intron 9, including the authentic donor splice site of exon 9. The large deletion of 72 bp was located in the same F12 gene region as the missense mutations p.Thr328Lys* and p.Thr328Arg* reported previously. Our findings confirm the association between F12 gene mutations modifying the proline-rich region of the FXII protein and hereditary angioedema with normal C1-inhibitor.

Kallikrein-kinin system and fibrinolysis in hereditary angioedema due to factor XII gene mutation Thr309Lys

In a subgroup of hereditary angioedema (HAE) patients with normal C1-esterase inhibitor levels, HAE is caused by a Thr309Lys mutation in the coagulation factor XII (F12) gene. The aim of this study was to examine elements of the kallikrein–kinin system (‘contact system’) and the downstream-linked coagulation, complement and fibrinolytic systems in the plasma of six patients with HAE caused by the Thr309Lys mutation and healthy probands. Blood samples were taken from participants during the symptom-free interval between attacks. Samples were analyzed for activity and concentrations of components of the kallikrein–kinin system and linked enzyme systems. The mean FXII clotting activity was 90% in patients with the FXII mutation, and the concentration of FXIIa was 4.1 ng/ml; this did not differ from healthy probands. Mean prekallikrein amidolytic activity and high-molecular-weight kininogen clotting activity were 130 and 144%, respectively, both higher than in healthy probands. The mean kallikrein-like activity of the HAE patients was 11.4 U/l and did not differ from healthy probands. There was no difference in FXII surface activation by silicon dioxide or in kallikrein-like activity with and without activation by dextran sulfate. Contrary to the results of a recently published study, no indication that the Thr309Lys mutation causes a ‘gain-of-function’ of FXIIa was observed in this investigation.

Hereditary angioedema with normal C1‐INH with versus without specific F12 gene mutations

Hereditary angioedema with normal C1‐INH may be linked to specific mutations in the coagulation factor 12 (FXII) gene (HAE‐FXII) or mutations in genes that are still unknown (HAE‐unknown). To assess the differences in transmission and inheritance, clinical features, and laboratory parameters between patients with HAE‐FXII and HAE‐unknown.

Hereditary angioedema with a mutation in the plasminogen gene

Hereditary angioedema (HAE) with normal C1‐INH (HAEnCI) may be linked to specific mutations in the coagulation factor 12 (FXII) gene (HAE‐FXII) or functional mutations in other genes that are still unknown. We sought to identify and characterize a hitherto unknown type of HAE with normal C1‐INH and without mutation in the F12 gene.

Treatment for hereditary angioedema with normal C1-INH and specific mutations in the F12 gene (HAE-FXII).

Hereditary angioedema with normal C1 esterase inhibitor and mutations in the F12 gene (HAE‐FXII) is associated with skin swellings, abdominal pain attacks, and the risk of asphyxiation due to upper airway obstruction. It occurs nearly exclusively in women. We report our experience treating HAE‐FXII with discontinuation of potential trigger factors and drug therapies. The study included 72 patients with HAE‐FXII. Potential triggers included estrogen‐containing oral contraceptives (eOC), hormonal replacement therapy, or angiotensin‐converting enzyme inhibitors. Drug treatment comprised plasma‐derived C1 inhibitor (pdC1‐INH) for acute swelling attacks and progestins, tranexamic acid, and danazol for the prevention of attacks. Discontinuation of eOC was effective in 25 (89.3%) of 28 women and led to a reduction in the number of attacks (about 90%). After ending hormonal replacement therapy, three of eight women became symptom‐free. Three women with exacerbation of HAE‐FXII during intake of quinapril or enalapril had no further HAE‐FXII attacks after discontinuation of those drugs. Eleven women were treated with pdC1‐INH for 143 facial attacks. The duration of the treated facial attacks (mean: 26.6 h; SD: 10.1 h) was significantly shorter than that of the previous 88 untreated facial attacks in the same women (mean: 64.1 h; SD: 28.0 h; P < 0.01). The mean reduction in attack frequency was 99.8% under progestins after discontinuing eOC (16 women), 93.8% under tranexamic acid (four women), and 100% under danazol (three women). For patients with HAE‐FXII, various treatment options are available which completely or at least partially reduce the number or duration of attacks.

Characterization of a partial exon 9/intron 9 deletion in the coagulation factor XII gene (F12) detected in two Turkish families with hereditary angioedema and normal C1 inhibitor

Hereditary angioedema (HAE) is clinically characterized by episodes of marked oedema involving the skin, gastrointestinal tract and other organs including the larynx. Until recently, HAE was assumed to result exclusively from a genetic deficiency of the C1-esterase inhibitor (C1-INH) (HAE-C1-INH). In 2000, ten families with normal C1-INH were reported in which HAE-C1-INH was ruled out [1]. Surprisingly, 36 women and no men were affected in these families. This disease was proposed to be termed as ‘HAE with normal C1 inhibitor occurring mainly in women’ (HAEnCI) or ‘HAE type III.’ [1] In 2006, two missense mutations encoded by exon 9 of the coagulation factor XII gene (F12) have been detected linked with HAEnCI [2]. Since then, a p.Thr328Lys substitution has been identified in clinically affected and symptomfree individuals from numerous families, whereas a p.Thr328Arg replacement has been found up to now only in two German families [3]. Two further F12 mutations were described in the meantime, a deletion and a duplication [4,5], both in-frame. All these F12 mutations affect the proline-rich region of the FXII protein. The association between these four F12 mutations and the HAEnCI phenotype provides strong support for the assumption that these mutations influence the development of a disease which is termed ‘HAE with mutations in the F12 gene’ or ‘HAE-FXII’. However, most patients with HAEnCI do not have alterations of the F12 gene (‘HAE without mutations in the F12 gene’ or ‘HAE-unknown’ [6]). In 2011, we identified the 72-bp F12 deletion (c.971_1018 + 24del72) in two Turkish women with HAE-FXII [4]. The mutation was located at the exon 9/intron 9 border and involved the proline-rich region of the factor XII protein (FXII) in which the two amino acid substitutions and the partial gene duplication mentioned above also are located. The aim of this study was to characterize the consequences of the partial F12 gene deletion on mRNA and protein synthesis. By haplotype analysis of the two seemingly unrelated families, we also wanted to determine, whether a single ancestral mutation is responsible for these cases. Among the patients with HAE-FXII seen in the Angioedema Outpatient Service of the Department of Dermatology at the Johannes Gutenberg University, Mainz, Germany, two unrelated Turkish families carrying the F12 c.971_1018 + 24del72 deletion were detected. All participants gave their informed consent, and approval for the study was obtained from the local ethics committee. Citrated plasma was used for all coagulation and protein determinations. C1-INH activity was determined using the chromogenic substrate C2H5CO-Lys (e-Cbo)-Gly-Arg-pNA (Technochrom C1-Inhibitor, Technoclone, Vienna, Austria). C1-INH antigen and C4 antigen were assayed by radial immunodiffusion (NOR Partigen C1-INH and C4, Siemens Healthcare Diagnostics, Marburg, Germany). Factor XII activity was measured by the one-stage method using factor XII-deficient plasma (Siemens Healthcare Diagnostics). Genomic DNA was isolated from blood cells by standard methods, followed by PCR amplification of exon 9, intron 9 and exon 10 of the F12 gene. Sequencing was performed using the Big Dye terminator cycle sequencing kit 3.1 (Applied Biosystems, Forster City, CA, USA), with the same primers used in the PCR reaction. Sequences obtained were compared with the consensus sequence of the Ensembl database 2012, using the reference sequence ENSG00000131187. The QIAamp RNA mini kit (QIAGEN, Hilden, Germany) was used for the isolation of total RNA from blood cells. Reverse transcription of the RNA was performed with the RevertAid H Minus kit from Fermentas (now Thermo Scientific, Pittsburgh, PA, USA), followed by PCR amplification with the same F12-specific primers located in exons 9 and 10 used for DNA sequence analysis. Two families of Turkish origin were identified who carried a deletion in the F12 gene in heterozygous Correspondence: Konrad Bork, M.D., Department of Dermatology, Johannes Gutenberg University, Langenbeckstr. 1, 55131 Mainz, Germany. Tel.: +49 6131 17 7290; fax: +49 6131 17 6614; e-mail: bork@hautklinik.klinik.uni-mainz.de

Antihistamine-resistant Angioedema in Women with Negative Family History: Estrogens and F12 Gene Mutations

BACKGROUND In women with sporadic recurrent angioedema with an unknown cause who are unresponsive to antihistamines and have normal C1 inhibitor activity and a negative family history of angioedema, it is unclear whether they have idiopathic angioedema or hereditary angioedema with normal C1 inhibitor, and what impact exogenous estrogens have on their angioedema. METHODS A cohort of 147 women was analyzed for F12 exon 9 mutations and for the influence of oral contraceptives, hormonal replacement therapy, and pregnancy on their angioedema. RESULTS A total of 142 women had idiopathic angioedema unresponsive to antihistamines. Five women had an F12 mutation and thereby hereditary angioedema with F12 mutations. Among the women with idiopathic angioedema, 63 had never taken estrogens. There was no estrogen impact in 42 women, a moderate impact in 15 women, and a severe impact in 22 women. The type and dose of estrogens did not differ in women with and without an estrogen impact. In 5 women, idiopathic angioedema disappeared after desogestrel use. Among the 5 women with hereditary angioedema with F12 mutations, angioedema symptoms occurred during 4 pregnancies, whereas no symptoms occurred during any of the 58 pregnancies in women with idiopathic angioedema. CONCLUSIONS Women with recurrent angioedema unresponsive to antihistamines may have idiopathic angioedema or, more rarely, hereditary angioedema with F12 mutations. Both conditions may be provoked or aggravated by exogenous estrogens. In idiopathic angioedema, treatment with progestins may be helpful.

Shortened Activated Partial Thromboplastin Time May Help in Diagnosing Hereditary and Acquired Angioedema

Objective: To evaluate whether activated partial thromboplastin time (APTT) could be used in the laboratory diagnosis of hereditary or acquired angioedema (HAE or AAE) with and without C1 inhibitor (C1-INH) deficiency. Methods: In a prospective investigation, APTT and other coagulation parameters were determined in 149 adult patients with various types of angioedema and in 26 healthy participants (HP). Results: Mean APTT was significantly shortened in HAE-C1-INH type I (p < 0.0001) and type II (p = 0.0017) and in AAE-C1-INH (p < 0.0001) compared to the HP. APTT was shortened under the reference range (26-36 s) in 33/45 (73.3%) patients with HAE-C1-INH, 10/15 (66.7%) patients with AAE-C1-INH, 4/27 (14.8%) patients with HAE with normal C1-INH, 1/32 (3.1%) patients with histaminergic angioedema, 4/30 (13.3%) patients with nonhistaminergic angioedema and in 2/26 (7.7%) HP. Thus, a shortened APTT was obtained in 8-9 times more patients with angioedema due to C1-INH deficiency when compared to patients with various forms of angioedema with normal C1-INH and also to HP. Conclusions: A shortened APTT may help to diagnose HAE-C1-INH and AAE-C1-INH when determination of C1-INH is not yet available.