Visceral manifestations in hereditary haemorrhagic telangiectasia type 2

Pathogenic Variant Frequencies in Hereditary Haemorrhagic Telangiectasia Support Clinical Evidence of Protection from Myocardial Infarction

Hereditary haemorrhagic telangiectasia (HHT) is a vascular dysplasia inherited as an autosomal dominant trait, due to a single heterozygous loss-of-function variant, usually in ACVRL1 (encoding activin receptor-like kinase 1 [ALK1]), ENG (encoding endoglin [CD105]), or SMAD4. In a consecutive single-centre series of 37 positive clinical genetic tests performed in 2021-2023, a skewed distribution pattern was noted, with 30 of 32 variants reported only once, but ACVRL1 c.1231C>T (p.Arg411Trp) identified as the disease-causal gene in five different HHT families. In the same centre's non-overlapping 1992-2020 series where 110/134 (82.1%) HHT-causal variants were reported only once, ACVRL1 c.1231C>T (p.Arg411Trp) was identified in nine further families. In a 14-country, four-continent HHT Mutation Database where 181/250 (72.4%) HHT-causal variants were reported only once, ACVRL1 c.1231C>T (p.Arg411Trp) was reported by 12 different laboratories, the adjacent ACVRL1 c.1232G>A (p.Arg411Gln) by 14, and ACVRL1 c.1120C>T (p.Arg374Trp) by 18. Unlike the majority of HHT-causal ACVRL1 variants, these encode ALK1 protein that reaches the endothelial cell surface but fails to signal. Six variants of this type were present in the three series and were reported 6.8-25.5 (mean 8.9) times more frequently than the other ACVRL1 missense variants (all p-values < 0.0039). Noting lower rates of myocardial infarction reported in HHT, we explore potential mechanisms, including a selective paradigm relevant to ALK1's role in the initiating event of atherosclerosis, where a plausible dominant negative effect of these specific variants can be proposed. In conclusion, there is an ~9-fold excess of kinase-inactive, cell surface-expressed ACVRL1/ALK1 pathogenic missense variants in HHT. The findings support further examination of differential clinical and cellular phenotypes by HHT causal gene molecular subtypes.

Prevalence and risk factors for bleeding in hereditary hemorrhagic telangiectasia: a National Inpatient Sample study

Hereditary hemorrhagic telangiectasia (HHT) is a common bleeding disorder, but little is known regarding prevalence and risk factors for bleeding. Adult discharges with HHT and bleeding were identified by International Classification of Disease, 10th edition (ICD-10) codes in the National Inpatient Sample (NIS), 2016-2018. Prevalence estimates were weighted using NIS discharge-level weights to reflect national estimates. Risk factors for bleeding were determined by weighted multivariable logistic regression. Among 18 170 849 discharges, 2528 (0.01%) had HHT, of whom 648 (25.6%) had bleeding. Arteriovenous malformation (AVM) (31.9% vs 1.3%), angiodysplasia (23.5% vs 2.3%), telangiectasia (2.3% vs 0.2%), and epistaxis (17.9% vs 0.6%) were more common in HHT than in non-HHT patients (non-HHT), each P < .001. In contrast, menstrual (HMB) and postpartum bleeding (PPH) were less common in reproductive-age HHT than non-HHT, each P < .001. Anemia associated with iron deficiency (IDA), was equally common in HHT with or without bleeding (15.7% vs 16.0%), but more common than in non-HHT (7.5%), P < .001. Comorbidities, including gastroesophageal reflux (25.9% vs 20.0%) and cirrhosis (10.0% vs 3.6%) were greater in HHT than non-HHT, each P < .001. In multivariable logistic regression, peptic ulcer disease (OR, 8.86; P < .001), portal vein thrombosis (OR, 3.68; P = .006), and hepatitis C, (OR, 2.13; P = .017) were significantly associated with bleeding in HHT. In conclusion, AVM and angiodysplasia are more common and HMB and PPH less common in patients in those with HHT than non-HHT. IDA deficiency is as common in HHT with and without bleeding, suggesting ongoing blood loss and need for universal iron screening.

Generation of a Syngeneic Heterozygous ACVRL1(wt/mut) Knockout iPS Cell Line for the In Vitro Study of HHT2-Associated Angiogenesis

Hereditary hemorrhagic telangiectasia (HHT) type 2 is an autosomal dominant disease in which one allele of the ACVRL1 gene is mutated. Patients exhibit disturbances in TGF-beta/BMP-dependent angiogenesis and, clinically, often present with severe nosebleeds as well as a reduced quality of life. The aim of our study was to use CRISPR/Cas9 to knockout ACVRL1 in normal induced pluripotent stem cells (iPSCs) and evaluate the effects on TGF-beta- and BMP-related gene expression as well as angiogenesis. The CRISPR/Cas9 knockout of the ACVRL1 gene was carried out in previously characterized wild-type (ACVRL1^wt/wt) iPSCs. An HHT type 2 iPS cell line was generated via a single-allele knockout (ACVRL1^wt/mut) in wild-type (ACVRL1^wt/wt) iPSCs, resulting in a heterozygous 17 bp frameshift deletion in the ACVRL1 gene [NG_009549.1:g.13707_13723del; NM_000020.3:c.1137_1153del]. After the generation of embryoid bodies (EBs), endothelial differentiation was induced via adding 4 ng/mL BMP4, 2% B27, and 10 ng/mL VEGF. Endothelial differentiation was monitored via immunocytochemistry. An analysis of 151 TGF-beta/BMP-related genes was performed via RT-qPCR through the use of mRNA derived from single iPS cell cultures as well as endothelial cells derived from EBs after endothelial differentiation. Differential TGF-beta/BMP gene expression was observed between ACVRL1^wt/wt and ACVRL1^wt/mut iPSCs as well as endothelial cells. EBs derived from CRISPR/Cas9-designed ACVRL1 mutant HHT type 2 iPSCs, together with their isogenic wild-type iPSC counterparts, can serve as valuable resources for HHT type 2 in vitro studies.

Evolution of Pulmonary Arteriovenous Malformations: The Role of Contrast Echocardiography

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) are direct connections between the pulmonary artery and the pulmonary vein, mostly associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs can lead to severe neurologic complications such as stroke and brain abscess. The risk of complications decreases after embolization. Therefore, screening for PAVMs using transthoracic contrast echocardiography (TTCE) is recommended, including a rescreening interval of 5 years.

RESEARCH QUESTION

Is extension of the interval for rescreening patients without a pulmonary right-to-left shunt (RLS) of up to 10 years appropriate?

STUDY DESIGN AND METHODS

Adult patients with HHT with 5- or 10-year follow-up TTCE, or both, were included. Patients who underwent PAVM embolization in the past or at baseline were excluded. The RLS grades and presence of a treatable PAVM were compared with baseline.

RESULTS

In total, 387 patients (median age, 45 years [interquartile range, 33-54 years]; 56% women) involving 5- and 10-year follow-up data in 363 and 166 patients, respectively, were included. None of the patients (n = 148) without a pulmonary RLS at baseline demonstrated a treatable PAVM after 5 and 10 years. Of the patients with a pulmonary RLS at baseline, 20 patients (9%) and three patients (3%) demonstrated a treatable PAVM at the 5- and 10-year follow-up, respectively. In most patients, the RLS grade remained stable over time.

INTERPRETATION

On the basis of the results of this retrospective study, we believe that the rescreening interval for patients with HHT without a pulmonary RLS at initial screening may be extended to 10 years. Those with a pulmonary RLS should be rescreened every 5 years because treatable PAVMs can evolve.

An update on the ophthalmic features in hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary haemorrhagic telangiectasia (HHT) or Osler-Rendu-Weber syndrome is a rare autosomal dominant disease, characterised by systemic angiodysplasia. Dysfunction of the signalling pathway of β transforming growth factor is the main cause of HHT principally owing to mutations of the genes encoding for endoglin (ENG) and activin A receptor type II-like 1 (ACVRL1). Clinical manifestations can range from mucocutaneous telangiectasia to organ arterio-venous malformations and recurrent epistaxis. The early clinical manifestations may sometimes be subtle, and diagnosis may be delayed. The main ophthalmic manifestations historically reported in HHT are haemorrhagic epiphora, and conjunctival telangiectasia present in 45-65% of cases, however, imaging with wide-field fluorescein angiography has recently shown peripheral retinal telangiectasia in 83% of patients. Optimal management of HHT requires both understanding of the clinical presentations and detection of early signs of disease. Advances in imaging methods in ophthalmology such as wide-field fluorescein angiography, spectral domain optical coherence tomography, and near infrared reflectance promise further insight into the ophthalmic signs of HHT towards improved diagnosis and early management of possible severe complications.

A retrospective cohort study on European Reference Network for Rare Vascular Diseases 5 outcome measures for Hereditary Haemorrhagic Telangiectasia in Denmark

Background

Hereditary Haemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by several clinical symptoms including epistaxis, arteriovenous malformations (AVM), and telangiectasia. In 2018, European Reference Network for Rare Vascular Diseases (VASCERN) recommended five outcome measures for HHT-patients to guide health care providers, some with limited experience in treating HHT, and thereby maximizing the number of HHT-patients receiving good care. The outcome measures cover the following aspects: (1) 90% of the patients should receive a pulmonary AVM (PAVM) screening; (2) 90% of the patients should receive written advice on nosebleed; (3) 70% should be assessed for iron deficiency; (4) 100% of the patients should receive written advice on antibiotic (AB) prophylaxis prior to dental and surgical procedures, and (5) 100% of relevant patients should receive written advice on pregnancy. We have introduced the outcome measures as Benchmarks in our HHT-centre and wanted to evaluate the extend of implementation we have achieved. We constantly struggle to secure the best possible treatment of our HHT-patients.

Methods

The study was a non-interventional retrospective study. Data was collected manually from patient records and from the Danish HHT-database.

Results

A total of 180 HHT-patients were included, all diagnosed in the period from January 1st, 2016, to December 31st, 2020. All patients were screened for PAVM. We could confirm that 66% of patients who had epistaxis received thoroughly advice. Assessment for iron deficiency was performed in 80% of the adult patients. Thoroughly advice on AB prophylaxis was documented in 75%. Thoroughly advice on pregnancy was documented in 80% of female patients 15–45 years of age. There were no significant differences over time for any of the outcome measures.

Conclusions

The Danish HHT-centre reached the target threshold for outcome measures 1 and 3. It could not be documented that the target thresholds for outcome measures 2, 4, and 5 were achieved. As information and education are a very important part of HHT care, focus on and documentation that all patients receive the relevant advice must be a priority in order to ensure best care.

Imaging Manifestations and Interventional Treatments for Hereditary Hemorrhagic Telangiectasia

Hemorrhagic hereditary telangiectasia (HHT) is a rare autosomal dominant disorder that causes multisystem vascular malformations including mucocutaneous telangiectasias and arteriovenous malformations (AVMs). Clinical and genetic screening of patients with signs, symptoms, or a family history suggestive of HHT is recommended to confirm the diagnosis on the basis of the Curaçao criteria and prevent associated complications. Patients with HHT frequently have epistaxis and gastrointestinal bleeding from telangiectasias. Pulmonary AVMs are common right-to-left shunts between pulmonary arteries and veins that can result in dyspnea and exercise intolerance, heart failure, migraine headaches, stroke or transient ischemic attacks, brain abscesses, or in rare cases, pulmonary hemorrhage. Primary neurologic complications from cerebral AVMs, which can take on many forms, are less common but particularly severe complications of HHT. Multimodality imaging, including transthoracic echocardiography, Doppler US, CT, and MRI, is used in the screening and initial characterization of vascular lesions in patients with HHT. Diagnostic angiography is an important tool in characterization of and interventional treatments for HHT, particularly those in the lungs and central nervous system. A multidisciplinary approach to early diagnosis, treatment, imaging, and surveillance at high-volume HHT Centers of Excellence is recommended. Although a variety of idiopathic, traumatic, or genetic conditions can result in similar clinical and imaging features, the Curaçao criteria are particularly useful for the proper diagnosis of HHT. Imaging and treatment options are reviewed, with a focus on screening, diagnosis, and posttreatment findings, with the use of updated international guidelines. Online supplemental material is available for this article. ^©RSNA, 2021.

An international, multicenter study of intravenous bevacizumab for bleeding in hereditary hemorrhagic telangiectasia: the InHIBIT-Bleed study

Hereditary hemorrhagic telangiectasia (HHT, Osler-Weber-Rendu disease) is a rare multisystem vascular disorder that causes chronic gastrointestinal bleeding, epistaxis, and severe anemia. Bevacizumab, an anti-vascular endothelial growth factor antibody, may be effective to treat bleeding in HHT. This international, multicenter, retrospective study evaluated the use of systemic bevacizumab to treat HHTassociated bleeding and anemia at 12 HHT treatment centers. Hemoglobin, Epistaxis Severity Score (ESS), red cell units transfused, and intravenous iron infusions before and after treatment were evaluated using paired means testing and mixed-effects linear models. Bevacizumab was given to 238 HHT patients for a median of 12 (range, 1-96) months. Compared with pretreatment, bevacizumab increased mean hemoglobin by 3.2 g/dL (95% confidence interval: 2.9-3.5 g/dL); i.e., from a mean hemoglobin of 8.6 (8.5-8.8) g/dL to 11.8 (11.5-12.1) g/dL; P<0.0001) and decreased the ESS by 3.4 (3.2-3.7) points (mean ESS 6.8 [6.6-7.1] versus 3.4 [3.2-3.7]; P<0.0001) during the first year of treatment. Compared with 6 months before treatment, the number of red blood cell units transfused decreased by 82% (median of 6.0 [interquartile range, 0.0-13.0] units versus 0 [0.0-1.0] units; P<0.0001) and iron infusions decreased by 70% (median of 6.0 [1.0-18.0] infusions versus 1.0 [0.0-4.0] infusions, P<0.0001) during the first 6 months of bevacizumab treatment. Outcomes were similar regardless of the underlying pathogenic mutation. Following initial induction infusions, continuous/scheduled bevacizumab maintenance achieved higher hemoglobin and lower ESS than intermittent/as-needed maintenance but with more drug exposure. Bevacizumab was well tolerated: hypertension, fatigue, and proteinuria were the most common adverse events. Venous thromboembolism occurred in 2% of patients. In conclusion, systemic bevacizumab was safe and effective for managing chronic bleeding and anemia in HHT.

Founder Effects in Hereditary Hemorrhagic Telangiectasia

A founder effect can result from the establishment of a new population by individuals from a larger population or bottleneck events. Certain alleles may be found at much higher frequencies because of genetic drift immediately after the founder event. We provide a systematic literature review of the sporadically reported founder effects in hereditary hemorrhagic telangiectasia (HHT). All publications from the ACVRL1, ENG and SMAD4 Mutation Databases and publications searched for terms “hereditary hemorrhagic telangiectasia” and “founder” in PubMed and Scopus, respectively, were extracted. Following duplicate removal, 141 publications were searched for the terms “founder” and “founding” and the etymon “ancest”. Finally, 67 publications between 1992 and 2020 were reviewed. Founder effects were graded upon shared area of ancestry/residence, shared core haplotypes, genealogy and prevalence. Twenty-six ACVRL1 and 12 ENG variants with a potential founder effect were identified. The bigger the cluster of families with a founder mutation, the more remarkable is its influence to the populational ACVRL1/ENG ratio, affecting HHT phenotype. Being aware of founder effects might simplify the diagnosis of HHT by establishing local genetic algorithms. Families sharing a common core haplotype might serve as a basis to study potential second-hits in the etiology of HHT.

Ocular lesions in hereditary hemorrhagic telangiectasia: genetics and clinical characteristics

Background

The aim of our study is to study the association between eye lesions in Hereditary Hemorrhagic Telangiectasia (HHT) and other signs of the disease, as well as to characterize its genetics.

Methods

A cross-sectional study was conducted of a cohort of 206 patients studied in the HHT Unit of Hospital de Sierrallana, a reference centre for Spanish patients with HHT. Odds ratios for several symptoms or characteristics of HHT and ocular lesions were estimated using logistic regression adjusting for age and sex.

Results

The ocular involvement was associated with being a carrier of a mutation for the ENG gene, that is, suffering from a type 1 HHT involvement (OR = 2.09; 95% CI [1.17–3.72]). p = 0.012). In contrast, patients with ocular lesions have less frequently mutated ACVRL1/ALK1 gene (OR = 0.52; 95% CI [0.30–3.88], p = 0.022).

Conclusions

In conclusion, half of the patients with HHT in our study have ocular involvement. These eye lesions are associated with mutations in the ENG gene and ACVRL1/ALK1 gene. Thus, the ENG gene increases the risk of ocular lesions, while being a carrier of the mutated ACVRL1/ALK1 gene decreases said risk.

Healthcare Utilization and Costs associated with Hereditary Hemorrhagic Telangiectasia Patients in a Large US Claims Database

Objective

To assess the health care costs and utilization in patients with hereditary hemorrhagic telangiectasia (HHT) in the United States.

Patients and Methods

Retrospective analysis of patients with HHT diagnosed between 2007 and 2017 was performed using deidentified administrative claims data from the OptumLabs Data Warehouse. Adult patients with new (incident) diagnosis of HHT between January 1, 2007, and December 31, 2017, were included. Comparisons were made using the Wilcoxon rank sum test.

Results

Three thousand nine hundred seventy-seven patients with a first diagnosis of HHT between 2007 and 2017 were identified, of which 3590 were matched 1:1 to non-HHT patients with similar baseline characteristics and comorbidities. These 3590 patients with HHT were 63.1% female and 83.9% white with a mean age of 51.1 ± 18.5 years, and a mean follow-up period of 3.2 ± 2.2 years (range, 1.0-11.7 years). Compared with the control group, the cumulative 5-year median total health care cost for patients with HHT was 41.4% higher ($21,118 vs $14,929; P < .001) in those with private commercial insurance and 31.7% higher ($35,462 vs $26,925; P < .001) in those with Medicare Advantage coverage. The median annual health care costs were significantly higher in patients with HHT with commercial insurance and Medicare Advantage in the first year after diagnosis ($4,333 vs $1,804; P < .001), and ($7,322 vs $5,245; P < .001), respectively, and remained higher throughout the duration of follow-up. Further analysis showed that outpatient clinic visits, hospital admission, imaging rates, invasive procedures, iron infusions, and blood transfusions were all significantly higher in the HHT group.

Conclusion

Patients with HHT have significantly higher health care costs compared with a matched control group. A better understanding of the reasons underlying these cost differences will provide opportunities for patients, providers, and other stakeholders to better manage this rare condition.

Intravenous Bevacizumab in Hereditary Hemorrhagic Telangiectasia-Related Bleeding and High-Output Cardiac Failure: Significant Inter-Individual Variability in the Need for Maintenance Therapy

OBJECTIVE

To present our center's experience with a maintenance treatment algorithm for intravenous bevacizumab that allows for personalized therapy decisions.

PATIENTS AND METHODS

We reviewed all patients treated with intravenous bevacizumab for hereditary hemorrhagic telangiectasia-related bleeding and/or high-output cardiac failure (HOCF) from January 1, 2013, to July 1, 2019, at the Mayo Clinic, Rochester, Minnesota. Data regarding subsequent bevacizumab dosing were abstracted.

RESULTS

A total of 57 patients (n=40, 70.2% females) were identified with a median age of 65 (55 to 74; range, 37 to 89) years. High-cardiac output state was present in 21 patients (36.8%) and 10 (17.5%) were treated with intravenous bevacizumab primarily for HOCF. The median duration of follow-up after completion of the initial intravenous bevacizumab treatment was 25 (12.3 to 40.8; range, 0.1 to 65.4) months. A total of 20 (35.1%) patients with a median follow-up of 13.5 (range, 0 to 48.4) months required no maintenance dosing throughout the duration of follow-up. Among those who required subsequent maintenance doses, only a small fraction (8 patients; 14.0%) required regular maintenance doses every 4 to 8 weeks during follow-up whereas the majority of patients required intermittent "as-needed" doses at varying intervals.

CONCLUSION

There is significant inter-individual variability in the need for maintenance intravenous bevacizumab when patients are followed using a predefined bevacizumab maintenance dosing treatment algorithm. The use of "as-needed" maintenance bevacizumab appears to be an effective strategy for management of hereditary hemorrhagic telangiectasia-related bleeding and HOCF.

An international survey to evaluate systemic bevacizumab for chronic bleeding in hereditary haemorrhagic telangiectasia

INTRODUCTION

Systemic bevacizumab is a novel targeted therapy for severe epistaxis and chronic gastrointestinal bleeding in hereditary haemorrhagic telangiectasia (HHT), but published data are very limited.

AIM

We conducted a survey-based study to characterize current treatment practices and physician-reported safety and effectiveness of systemic bevacizumab for bleeding in (HHT).

METHODS

A 27-item survey was sent to physician centre directors of 31 International HHT Centers of Excellence.

RESULTS

Response rate was 84%. Approximately half of centres had treated >10 HHT patients with systemic bevacizumab for chronic bleeding for a total of 291 patients treated. All centres utilize a 5 mg/kg dose for induction treatment and most administer six doses (range, 4-8) every 2 weeks. However, maintenance regimens varied considerably between centres. Bevacizumab was highly effective, with 86% reporting significant (>50%) improvement in GI bleeding and/or epistaxis and haemoglobin rise in most patients treated with bevacizumab; 52% reported haemoglobin normalization in most patients. All centres reported adverse event rates <30% and two-thirds of centres reported adverse event rates <10%. Discontinuation for adverse events or inefficacy was rare. Bleeding severity thresholds for initiation of bevacizumab were highly variable, and it is typically administered by haematologists (76% of centres). Two-thirds of centres reported obtaining insurance approval for bevacizumab for most or all patients but 48% reported difficulty in obtaining coverage.

CONCLUSION

Systemic bevacizumab is widely used to treat bleeding in HHT with excellent physician-reported effectiveness and safety. There is considerable variation in maintenance treatment practices and thresholds for initiation of bevacizumab among HHT centres.

Systemic bevacizumab for high-output cardiac failure in hereditary hemorrhagic telangiectasia: an international survey of HHT centers

Background

Systemic bevacizumab is a novel targeted anti-angiogenic therapy for high-output cardiac failure (HOCF) in hereditary hemorrhagic telangiectasia (HHT) but published data is limited. This survey-based study measured physician-reported safety, effectiveness and current treatment practices for systemic bevacizumab in HHT-HOCF.

Methods

A 27-item survey was sent to center directors of 31 international HHT Centers of Excellence.

Results

Response rate was 74% with centers reporting 150 total patients receiving systemic bevacizumab for HHT-HOCF. Approximately two-thirds of centers had treated ≥5 patients. All centers utilize a 5 mg/kg dose for induction treatment and most administer 6 doses (range, 4–6) every 2 weeks, although maintenance regimens varied considerably. Center directors reported bevacizumab to be effective, with 55% reporting significant improvement in cardiac index and HOCF symptoms in most patients treated with bevacizumab, although normalization of cardiac parameters was uncommon. Adverse events were uncommon with three-quarters of centers reporting adverse event rates < 10%. Discontinuation for adverse events or ineffectiveness was rare. Bevacizumab was typically administered by hematologists and pulmonologists (50 and 39% of centers, respectively), with highly variable thresholds for initiation. Although half the centers reported difficulty with the insurance approval process, 70% of centers were ultimately able to obtain coverage for most or all of their patients.

Conclusions

Systemic bevacizumab is a widely-used therapy for HHT-HOCF with reasonable safety and effectiveness. HHT centers appear to vary considerably in maintenance treatment practices and disease severity thresholds for initiation of bevacizumab in HHT-related HOCF.

Variant analysis in Chinese families with hereditary hemorrhagic telangiectasia

Background

Hereditary hemorrhagic telangiectasia (HHT) is a vascular dysplasia disorder characterized by epistaxis, mucocutaneous telangiectasias and arteriovenous malformations in internal organs. Recurrent epistaxis is the primary complaint in 90%‐96% of HHT patients and the other symptoms come with age. The aim of this study was to analyze HHT‐associated gene variant spectrum in Chinese HHT patients and to assess whether genetic testing could contribute to the early diagnosis.

Methodology/Principal

Thirty one HHT families including 62 individuals were recruited. Variants in the coding regions of four genes involved in HHT were amplified and analyzed using Sanger sequencing and multiplex ligation‐dependent probe amplification (MLPA).

Results

Twenty unique variants, including 8 novel variants were found in 24 of the 31 (77.4%) kindred. Diagnosis is confirmed for 7 possible individuals from 6 kindred. Thirteen ACVRL1 variants were detected from 17 isolated HHT families. Variants in ACVRL1 from 8/17 (47.1%) families were located in exon8. Seven ENG variants were found in 7 unrelated families throughout the coding region.

Conclusion

We conclude that ACVRL1 gene variant is 2.4 times more prevalent than that in ENG in Chinese individuals with HHT, and exon8 of the ACVRL1 gene may be a hotspot region. Genetic testing could contribute to early diagnosis for HHT.

Mutations in Chromatin Modifier and Ephrin Signaling Genes in Vein of Galen Malformation

Normal vascular development includes the formation and specification of arteries, veins, and intervening capillaries. Vein of Galen malformations (VOGMs) are among the most common and severe neonatal brain arterio-venous malformations, shunting arterial blood into the brain's deep venous system through aberrant direct connections. Exome sequencing of 55 VOGM probands, including 52 parent-offspring trios, revealed enrichment of rare damaging de novo mutations in chromatin modifier genes that play essential roles in brain and vascular development. Other VOGM probands harbored rare inherited damaging mutations in Ephrin signaling genes, including a genome-wide significant mutation burden in EPHB4. Inherited mutations showed incomplete penetrance and variable expressivity, with mutation carriers often exhibiting cutaneous vascular abnormalities, suggesting a two-hit mechanism. The identified mutations collectively account for ∼30% of studied VOGM cases. These findings provide insight into disease biology and may have clinical implications for risk assessment.

Systemic bevacizumab for the treatment of chronic bleeding in hereditary haemorrhagic telangiectasia

BACKGROUND

Hereditary haemorrhagic telangiectasia (HHT) is a rare hereditary multisystem vascular disorder causing visceral arteriovenous malformations and mucocutaneous bleeding. Chronic gastrointestinal bleeding and epistaxis often produce profound anaemia refractory to conventional treatment. Bevacizumab, an anti-vascular endothelial growth factor monoclonal antibody, may be effective in treatment of bleeding in HHT.

METHODS

All HHT patients treated with systemic bevacizumab for chronic bleeding were selected for retrospective analysis. Data collected included demographics, baseline HHT characteristics, epistaxis grade, surgical interventions, bevacizumab dosing, adverse events, haemoglobin, red cell transfusions, intravenous iron infusions, and other anaemia and/or bleeding-directed therapies.

RESULTS

Thirteen HHT patients were treated with bevacizumab for a median of 13.9 (range 4.9-30.1) months. Compared with pretreatment values, bevacizumab treatment increased the mean haemoglobin by 4.0 g dL^-1 (95% CI, 2.6-5.3 g dL^-1 ) [mean (95% CI) haemoglobin 8.5 (7.8, 9.9) g dL^-1 vs. 12.5 (11.2, 13.7) g dL^-1 , P < 0.001)], reduced red cell units transfused by 92% [median of 6 (range 0-59) units vs. 0 (range 0-15) units, P = 0.004] and reduced quantity of iron infused by 73% [mean (95% CI) 462 (257, 668) mg month^-1 vs. 126 (75, 178) mg month^-1 , P = 0.002]. Epistaxis control was achieved in 85% with bevacizumab versus 0% before treatment (P < 0.001). No patient required nasal or GI procedures during the maintenance period. Two patients (15%) developed grade 3 hypertension requiring medical management.

CONCLUSION

Systemic bevacizumab was highly effective to treat chronic bleeding in HHT. Further study is needed to confirm the magnitude of benefit and further define optimal dosing, treatment duration and long-term safety.

Prenatal care and labor in patients with mesenchimal dysplasias (Marfan syndrome, Ehlers-Danlos syndrome, hereditary hemorrhagic telangiectasia)

Background: Mesenchymal dysplasias or inherited connective tissue diseases are the group of diseases with deficiency of various components of connective tissue. Connective tissue disorders can affect different organs: skeleton, sight organ, skin, lungs, heart. But the most dangerous is vascular wall insufficiency leading to high risk of hemorrhage, especially during pregnancy and delivery due to hemodynamic and hormonal effects on the walls of the modified vessels.Aim: To evaluate the risk of complications during the pregnancy and delivery in patients with mesenchymal dysplasias.Study design: Fifty-six pregnancies in patients with mesenchymal dysplasias, including subclinical forms of diseases: 23 with Marfan syndrome (I group), 22 with Ehlers-Danlos syndrome (II group), and 11 with Osler-Weber-Rendu syndrome (hereditary hemorrhagic telangiectasia) (III group) of the age from 18 to 36. The study included retrospective analysis (for the period from 1993 to 2005) and prospective study. Results of study showed high risk of life-threatening complications during pregnancy and delivery, especially the risk of hemorrhage and cardiovascular complications. In all the patients, we observed the progression of bleeding or development of bleeding in new localizations (epistaxis in 27 patients, easy brushing in 22, skin and mucosa telangiectasia in 20, gastrointestinal bleedings in 4, hemoptysis in 4, hematomas for minor traumas in 14, conjunctivas hemorrhages in 5).Conclusion: The pathogenesis of bleeding in such patients has mixed pattern: besides vascular wall pathology coagulation deficiency plays some role. The preferred delivery method for such patients is caesarean section. Deep vaginal ruptures and serious hemorrhage accompany vaginal delivery.

Mutations in the ENG, ACVRL1, and SMAD4 genes and clinical manifestations of hereditary haemorrhagic telangiectasia: experience from the Center for Osler's Disease, Uppsala University Hospital

AIM

The aim of this retrospective single-centre study was to evaluate whether mutations in the ENG, ACVRL1, and SMAD4 genes were associated with different phenotypes in hereditary haemorrhagic telangiectasia (HHT).

METHODS

The case records of 21 HHT patients with verified mutations in ENG, ACVRL1, or SMAD4 genes were reviewed. The numbers of HHT diagnostic criteria fulfilled for the three genotypes were compared, as was the prevalence of complications such as iron deficiency anaemia, gastrointestinal haemorrhage, stroke, and cerebral abscess.

RESULTS

Our results indicate that mutations in the ENG (HHT1), ACVRL1 (HHT2), and SMAD4 genes result in different HHT phenotypes. Epistaxis debuts earlier and may be more severe in HHT1 than in HHT2. The prevalence of pulmonary arteriovenous malformations (AVM) is higher in HHT type 1, whereas hepatic AVMs are more common in HHT2. One patient with mutations in both ENG and ACVRL1 genes was identified, as were two SMAD4-mutated patients suffering from the overlapping juvenile polyposis-HHT syndrome. Nearly one in five patients in our HHT population has been diagnosed with stroke or cerebral abscess, indicating a high prevalence of cerebral complications.

CONCLUSION

Our results showing that ENG and ACVRL1 gene mutations result in different HHT phenotypes confirm the results from other HHT centres worldwide. Cerebral complications of HHT are common, underscoring the importance of regular screening for pulmonary AVMs and early intervention against such AVMs. We have identified an HHT patient with simultaneous mutations in the ENG and ACVRL1 genes. Surprisingly, this patient has had a mild course of the disease.

New Classification of Nasal Vasculature Patterns in Hereditary Hemorrhagic Telangiectasia

Background

Hereditary hemorrhagic telangiectasia (HHT) is a disorder characterized by the triad of recurrent epistaxis, telangiectasia, and a family history of the disease. Management of recalcitrant epistaxis in HHT remains a challenging problem for otolaryngologists. The precise coagulation of telangiectasias with the Nd-YAG laser has shown efficacy in the treatment of HHT-associated epistaxis, but results can be variable and patient selection is critical in ensuring a successful outcome. We propose a new classification of nasal vasculature patterns in HHT as a means for selecting the Nd-YAG laser for photocoagulation treatment.

Methods

The records of 40 patients who underwent Nd-YAG laser photocoagulation for HHT were reviewed retrospectively. Outcomes after Nd-YAG laser treatment were correlated with three observed nasal vasculature patterns: (I) isolated punctate telangiectasias or individual small arteriovenous malformation; (II) diffuse interconnecting vasculature with “feeder” vessels; and (III) large solitary arteriovenous malformation, which may be associated with scattered telangiectasia.

Results

Types I and II were the most common vasculature patterns seen in this patient population. Patients with patterns I and III showed greater improvement in epistaxis after Nd-YAG laser photocoagulation. Patients with pattern II fared better with septodermoplasty.

Conclusion

These findings suggest that analysis of nasal vasculature patterns can improve therapeutic stratification of patients with HHT. Proper patient selection using this new classification scheme may improve the management of epistaxis in patients with HHT.

Gastrointestinal Manifestations of Hereditary Hemorrhagic Telangiectasia (HHT): A Systematic Review of the Literature

Hereditary hemorrhagic telangiectasia (HHT), also called Osler-Weber-Rendu syndrome, is an autosomal dominant genetic disease that affects the vasculature of numerous organs. The prevalence of HHT is estimated to be between 1.5 and 2 persons per 10,000. While there is still much to learn about this condition, there is an increasing understanding its underlying pathophysiology, genetic basis, presentations, and management. Recognizing that the clinical manifestations of HHT can involve a number of organ systems will provide clinicians with a higher index of suspicion for the disease. This early diagnosis and genotyping can greatly reduce mortality for a patient with HHT through appropriate screening for complications. This review will focus on the gastrointestinal manifestations of HHT and how these can dictate treatment and prognosis.

The Lung in Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a dominantly inherited genetic vascular disorder with an estimated prevalence of 1 in 6,000, characterized by recurrent epistaxis, cutaneous telangiectasia, and arteriovenous malformations (AVMs) that affect many organs including the lungs, gastrointestinal tract, liver, and brain. Its diagnosis is based on the Curaçao criteria, and is considered definite if at least 3 of the 4 following criteria are fulfilled: (1) spontaneous and recurrent epistaxis, (2) telangiectasia, (3) a family history, and (4) pulmonary, liver, cerebral, spinal, or gastrointestinal AVMs. The focus of this review is on delineating how HHT affects the lung.

High prevalence of pulmonary hypertension in patients with hereditary hemorrhagic telangiectasia

OBJECTIVE

Hereditary hemorrhagic telangiectasia (HHT) is a vascular disorder causing mucocutaneous telangiectases and visceral arteriovenous malformations (AVMs). Pulmonary hypertension (PH) is considered an uncommon complication of HHT whose impact on the survival of these patients is currently unknown.

METHODS

From January 1995 to December 2008, 29 hospitalized patients with definite HHT were included and followed until January 2011. Data on demographics, clinical symptoms and survival were recorded. PH was classified according to echocardiographic probability.

RESULTS

A CT angiogram was performed in 24 of the 29 patients with HHT and AVMs were detected in 16 of them (67%): hepatic in 58%, pulmonary in 33% and spinal in 3%; 37% had both pulmonary and hepatic AVMs. Transthoracic Doppler echocardiography (TTE) was performed in 21 patients. PH was considered possible in 4 (14%) and probable in 9 (31%). The mean age at diagnosis was lower in patients with PH than in patients without PH (54±16.5 years vs 73±8.8 years, p=0.002). PH was more prevalent in patients with AVMs (56 vs. 23%, p=0.036). The mean follow-up of the entire cohort was 6±4.4 years (range: 2 months-17 years), during this time 18 patients died (62%; mean age 73±8.1 years). Patients with PH died at a younger age (68±8.4 vs. 79±2.7 years, p=0.015) than those without PH.

CONCLUSIONS

PH is a severe condition that significantly reduces survival on HHT patients. PH should be suspected in all HHT patients with dyspnea and hepatic AVMs.

An intron mutation in the ACVRL1 may be associated with a transcriptional regulation defect in a Chinese family with hereditary hemorrhagic telangiectasia

Purpose

To identify a novel pathogenic gene mutation present in a Chinese family with hereditary hemorrhagic telangiectasia (HHT) and to determine if an intron mutation may influence the transcriptional activity of the ACVRL1 gene.

Methods

HHT family members were ascertained following the presentation of proband and involved subjects. All family members (n = 5) and 113 healthy individuals were genotyped for the variant in intron 6 c.772+27G>C of ACVRL1 gene. The genomic structure of ACVRL1 in affected HHT patients and healthy individuals was determined by long range PCR and sequencing. The expression of ACVRL1 mRNA and protein in patients with HHT was evaluated using real-time polymerase chain reaction and immunoblot analysis. Luciferase activity assay and electrophoretic mobility shift assay (EMSA) were performed to uncover the mechanism of intron-related transcriptional regulation.

Results

Only one novel mutation in intron 6 (c.772+27G>C) of ACVRL1 gene, no other mutation, abnormal splice, gross genomic deletion or rearrangement was found in this HHT2 family. Compared with healthy individuals, ACVRL1 mRNA and protein were significantly decreased in affected HHT2 individuals. Luciferase activity assay demonstrated that the transcriptional activity of the mutated ACVRL1 was significantly lower than that of the wild-type of intron 6; EMSA results showed that intron 6 c.772+27G>C mutation was able to inhibit the binding of transcriptional factor Sp1.

Conclusions

A novel intron mutation in ACVRL1 gene is associated with familial HHT2. The mechanisms may be involved in the down-regulation of ACVRL1 gene transcription.

Differential diagnosis of upper gastrointestinal bleeding proximal to the ligament of Trietz

Upper gastrointestinal bleeding (UGIB) is an important medical problem for patients and the medical system. The causes of UGIB are varied and their accurate identification guides appropriate management. The major cause of UGIB is peptic ulcer disease, for which Helicobacter pylori and nonsteroidal antiinflammatory drug use are major risk factors. Lesser causes include Dieulafoy lesion, gastric antral vascular ectasia, hemobilia, aortoenteric fistulas, and upper gastrointestinal tumors. Awareness of causes and management of UGIB should allow physicians to treat their patients more effectively.

Update on molecular diagnosis of hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant, vascular disease hallmarked by the development of arteriovenous malformations (AVMs). Germline mutations in two genes, endoglin (ENG) and activin receptor like kinase 1 (ACVRL1), have been implicated in this disease. This report describes molecular diagnosis in a consecutive series of 600 individuals with clinical features of HHT disease. Each coding exon and flanking intronic regions of ENG and ACVRL1 genes was sequenced. Exonic copy number was quantified in probands without a coding sequence mutation. Novel nonsynonymous variants were further analyzed to predict functional consequences. In addition, common single nucleotide polymorphisms genotypes and haplotypes for the two genes were compared between individuals with and without mutations. The highest mutation detection rate (87% [95% CI 80.2-91.5]) was observed in probands who met all four Curacao criteria (epistaxis, telangiectases, AVMs and family history). More than 30% of identified mutations were novel; however, only 6% were variants of unknown significance. Determining the significance of novel mutations as related to disease presents additional challenges. Detection of multiple alterations in the same proband also requires careful evaluation for disease association. In conclusion, the sensitivity of molecular diagnosis is highest in probands with a clinically confirmed diagnosis of HHT. However, a substantial fraction of probands in this group do not carry an identifiable mutation in the coding exons of these two genes. This suggests alternate mechanisms of gene inactivation or involvement of alternate loci, and it requires further investigation.

High diagnostic and clinical impact of small-bowel capsule endoscopy in patients with hereditary hemorrhagic telangiectasia with overt digestive bleeding and/or severe anemia

BACKGROUND

Patients with hereditary hemorrhagic telangiectasia (HHT) often present with recurrent anemia because of epistaxis or GI bleeding in relation to telangiectases mostly located in the stomach or small bowel. Capsule endoscopy is considered a major diagnostic tool for small-bowel diseases, but the impact of capsule endoscopy imaging on patient management in HHT is poorly understood.

OBJECTIVE

To clarify the contribution of capsule endoscopy in selected patients with HHT.

DESIGN

Prospective, descriptive study.

SETTING

Multicenter, two university hospital tertiary-care centers, from January 2003 to June 2007.

PATIENTS

This study involved 30 patients with HHT and severe anemia (hemoglobin <9 g/dL; normal: 11-15 g/dL) and minimal epistaxis or moderate anemia but overt GI bleeding.

INTERVENTION

Capsule endoscopy investigation.

MAIN OUTCOME MEASUREMENTS

Clinical characteristics and capsule endoscopy results and their clinical consequences.

RESULTS

Capsule endoscopy detected gastric and small-bowel telangiectases in 14 (46.7%) and 26 (86.7%) cases, respectively. Active bleeding was present in 36.7% of cases. Diffuse telangiectases were detected in 42.3% without correlation with age, sex, or type of HHT mutation. Further investigations were carried out as a consequence of the capsule endoscopy results in 67% of cases. Treatment, consisting mostly of endoscopic argon plasma coagulation, was scheduled in 46.7% of patients.

LIMITATIONS

Our population was essentially composed of patients with the ALK1 mutation.

CONCLUSION

This study shows that there is a high diagnostic yield for capsule endoscopy in selected patients with HHT. Capsule endoscopy makes possible precise mapping of lesions and has a considerable impact on the management of these selected patients by using a predefined algorithm: a limited number of accessible lesions is suitable for endoscopic treatment, whereas innumerable diffuse lesions require a medical approach. We suggest that capsule endoscopy could be a first-line, noninvasive, digestive tract examination in selected patients with HHT.

Hereditary Hemorrhagic Telangiectasia Presenting as High Output Cardiac Failure during Pregnancy

High-output cardiac failure secondary to hepatic involvement is a rare complication of hereditary hemorrhagic telangiectasia (HHT). Here we report a 43-year-old woman who presented at 29 weeks gestation of her second pregnancy with complications of right-sided heart failure and preterm labor. After delivery via cesarean section, the patient was found to have intrahepatic arteriovenous malformations through non-invasive imaging. Subsequently, a family history of vascular malformations and epistaxis was elucidated and a diagnosis of HHT was made. This case is presented, along with a review of the literature and discussion of hepatic involvement in HHT with particular focus on the pregnant patient.

Worsening of nose bleeding heralds high cardiac output state in hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia is characterized by arteriovenous malformations or telangiectasias in multiple organs. Nose bleeding is the most common manifestation of hereditary hemorrhagic telangiectasia and can be debilitating. Cardiac involvement in the form of high-output cardiac failure is a poorly studied complication of hereditary hemorrhagic telangiectasia. The objective of this study is to describe the natural history of high-output cardiac failure in hereditary hemorrhagic telangiectasia and define the relation between bleeding complications and high-output cardiac failure.

METHODS

In this case-control study at the Washington University hereditary hemorrhagic telangiectasia center, all patients evaluated for hereditary hemorrhagic telangiectasia and found to have high cardiac output between 1999 and 2006 were enrolled as cases (n = 17) and compared with 17 hereditary hemorrhagic telangiectasia controls without high-output cardiac failure.

RESULTS

During lifetime, cases needed more transfusions, emergency department visits, and hospital admission for nose bleeding. Cases experienced significant worsening of nose bleeding immediately before heart failure diagnosis. During the 2 years before study-related evaluation, 16 (94%) cases needed transfusions every month as compared with 2 (12%) controls (P <.001). The number of transfusions required during these 2 years also was higher in cases (median 3, range 0-12) as compared with controls (median 0, range 0-1.5, P <.001).

CONCLUSIONS

Hereditary hemorrhagic telangiectasia patients with high-output cardiac failure have significantly greater nose bleeding as compared with patients without high-output cardiac failure. In addition, nose bleeding worsens around the time of development of high-output cardiac failure. Early recognition of the relationship between severe nose bleeding and high-output cardiac failure can lead to earlier diagnosis and provide an opportunity for earlier institution of therapy for high-output cardiac failure.

Evaluation of previously nonscreened hereditary hemorrhagic telangiectasia patients shows frequent liver involvement and early cardiac consequences

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disease characterized by cutaneous, mucosal, and sometimes visceral arteriovenous malformations. Severe hepatic manifestations have been characterized in a subgroup of patients, but few data are available in previously nonscreened patients. We prospectively evaluated liver involvement and its cardiac consequences in such patients. Between 2000 and 2005, we prospectively evaluated the clinical, biological, and hepatic Doppler sonography (DS) characteristics of 102 consecutive HHT patients (mean age, 52.5 years; range, 19-88; 80.4%) with an identified genetic mutation. Patients were segregated into three different severity groups according to DS values. Factors predictive of an abnormal DS, according to predetermined criteria, and of a high cardiac index were identified by logistic and linear regression analysis, respectively. Abnormal liver biology and clinical signs of hepatic involvement were present in 35.3% and 27.5% of cases, respectively. Abnormal DS (defined as at least enlargement of the main hepatic artery) was observed in 56 (54.9%) cases, and direct or indirect signs of significant fistulas were present in 26 (25.5%) cases. Abnormal liver biology and a mutation involving the ACVRL1 gene were predictive of hepatic ultrasound (US) abnormalities. The diameter of the main hepatic artery and the presence of focal nodular hyperplasia (FNH) were predictive of a higher cardiac index.

CONCLUSION

This large prospective series of previously nonscreened HHT patients identified a subgroup at risk of liver involvement (patients with abnormal liver biology and ACVRL1 mutations) and a subgroup with a higher cardiac index: future studies will show whether such patients would benefit from systematic DS screening and long-term cardiac surveillance.

Mutation study of Spanish patients with hereditary hemorrhagic telangiectasia

Background

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant and age-dependent vascular disorder characterised mainly by mutations in the Endoglin (ENG) or activin receptor-like kinase-1 (ALK1, ACVRL1) genes.

Methods

Here, we have identified 22 ALK1 mutations and 15 ENG mutations, many of which had not previously been reported, in independent Spanish families afflicted with HHT.

Results

We identified mutations in thirty-seven unrelated families. A detailed analysis of clinical symptoms was recorded for each patient analyzed, with a higher significant presence of pulmonary arteriovenous malformations (PAVM) in HHT1 patients over HHT2. Twenty-two mutations in ALK1 and fifteen in ENG genes were identified. Many of them, almost half, represented new mutations in ALK1 and in ENG. Missense mutations in ENG and ALK1 were localized in a tridimensional protein structure model.

Conclusion

Overall, ALK1 mutations (HHT2) were predominant over ENG mutations (HHT1) in our Spanish population, in agreement with previous data from our country and other Mediterranean countries (France, Italy), but different to Northern Europe or North America. There was a significant increase of PAVM associated with HHT1 over HHT2 in these families.

Acute nonvariceal upper gastrointestinal bleeding: endoscopic diagnosis and therapy

Acute upper gastrointestinal bleeding is a relatively common,potentially life-threatening condition that causes more than 300,000 hospital admissions and about 30,000 deaths per annum in America. Esophagogastroduodenoscopy is the procedure of choice for the diagnosis and therapy of upper gastrointestinal bleeding lesions. Endoscopic therapy is indicated for lesions with high risk stigmata of recent hemorrhage, including active bleeding, oozing, a visible vessel, and possibly an adherent clot. Endoscopic therapies include injection therapy, such as epinephrine or sclerosant injection; ablative therapy, such as heater probe or argon plasma coagulation; and mechanical therapy, such as endoclips or endoscopic banding. Endoscopic therapy reduces the risk of rebleeding,the need for blood transfusions, the requirement for surgery, and patient morbidity.

American Gastroenterological Association (AGA) Institute technical review on obscure gastrointestinal bleeding

This literature review and the recommendations therein were prepared for the AGA Institute Clinical Practice and Economics Committee. The paper was approved by the Committee on March 12, 2007, and by the AGA Institute Governing Board on May 19, 2007.

Health-related quality of life in hereditary hemorrhagic telangiectasia

OBJECTIVE

To assess and differentiate the health-related quality of life (HR-QoL) in patients with hereditary hemorrhagic telangiectasia (HHT).

STUDY DESIGN AND SETTING

A prospective, open, cross-sectional questionnaire-based study (including the Short Form-36 Health Survey [SF-36]) performed by a tertiary care center.

RESULTS

A total of 77 patients (36 females) were included. Except for one domain (bodily pain), the scores for all scales of the SF-36 were significantly reduced in comparison with normative data. The duration of epistaxis, the presence of hepatic involvement and gastrointestinal bleeding, and the number of visible telangiectases correlated with lower scores on several scales of the SF-36. Unexpectedly, the frequency of epistaxis did not correlate with any scale.

CONCLUSIONS

The duration of epistaxis, liver involvement, gastrointestinal bleeding, and the number of visible telangiectases have a major influence on the HR-QoL in HHT whereby the frequency of epistaxis seems to play a minor role.

SIGNIFICANCE

The data presented have an impact on therapeutic decisions, medical expert opinions, and research funding.

Hereditary hemorrhagic telangiectasia: clinical features in ENG and ALK1 mutation carriers

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder characterized by epistaxis, mucocutaneous telangiectases and visceral arteriovenous malformations (AVMs), particularly in the brain (CAVMs), lungs (PAVMs), liver (HAVMs) and gastrointestinal tract (GI). The identification of a mutated ENG (HHT1) or ALK-1 (HHT2) gene now enables a genotype-phenotype correlation.

OBJECTIVE

To determine the incidence of visceral localizations and evaluate phenotypic differences between ENG and ALK1 mutation carriers.

METHODS

A total of 135 consecutive adult patients were subjected to mutational screening in ENG and ALK1 genes and instrumental tests to detect AVMs, such as chest-abdomen multislice computed tomography (MDCT), brain magnetic resonance imaging and magnetic resonance angiography (MRI/MRA), upper endoscopy, were offered to all patients, independent of presence of clinical symptoms. The 122 patients with identified mutations were enrolled in the study and genotype-phenotype correlations were established.

RESULTS

PAVMs and CAVMs were significantly more frequent in HHT1 (75% vs. 44%, P < 0.0005; 20% vs. 0%, P < 0.002, respectively) and HAVMs in HHT2 (60% vs. 84%, P < 0.01). No age difference was found for PAVMs whereas HAVMs were significantly higher in older patients in both HHT1 and HHT2. Neurological manifestations secondary to CAVMs/PAVMs were found only in HHT1 patients, whereas severe liver involvement was detected only in HHT2. Respiratory symptoms were mainly detected in HHT1.

CONCLUSIONS

Our study evidences a higher visceral involvement in HHT1 and HHT2 compared with previous reports. HHT1 is more frequently associated with congenital AVM malformations, such as CAVMs and PAVMs whereas HHT2 predominantly involves the liver. The ENG gene should be first targeted for mutational screening in the presence of large PAVM in patients < 45 years.

Clinical and analytical sensitivities in hereditary hemorrhagic telangiectasia testing and a report of de novo mutations

Hereditary hemorrhagic telangiectasia is a vascular dysplasia with variable onset and expression. Through identification of a mutation in a proband, mutation testing can be offered to family members. Mutation carriers can receive medical surveillance and treatment before potentially fatal complications arise. In this study, we assessed the significance of clinical evaluations as part of hereditary hemorrhagic telangiectasia diagnostic testing to determine the clinical sensitivity of molecular testing and to report novel mutations. Based on reported clinical symptoms, we classified 142 consecutive cases as affected, suspected, or unlikely affected. We performed temperature gradient capillary electrophoresis and full gene sequencing of both ACVRL1 and ENG genes. We then compared the mutation detection rates between these groups, categorizing sequence variants as mutations, variants of uncertain significance (VUS), or known polymorphisms. Our mutation and VUS detection rate in affected individuals was 74% and 16% in the suspected/unlikely affected group. Sixty-one percent of the mutations and all VUS were novel. The mutation detection rate for temperature gradient capillary electrophoresis was 97%. Our results suggest that a careful clinical evaluation increases the mutation detection rate. We have confirmed the occurrence of de novo mutations in three patients. Our results also show that temperature gradient capillary electrophoresis is an efficient mutation screening method.

Genotype-phenotype correlations in hereditary hemorrhagic telangiectasia: data from the French-Italian HHT network

PURPOSE

Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by arteriovenous malformations (AVM), mostly cutaneous and mucous (telangiectases), but also involving the lungs (PAVM), liver (HAVM) and brain (CAVM). We studied the relationship between the phenotype and genotype in patients with a proven mutation in either ENG (HHT1) or ACVRL1 (HHT2).

METHODS

Clinical features and their age of onset were compared between HHT1 and HHT2. The type of mutation was also analyzed. Clinical manifestations were distinguished from lesions found by screening.

RESULTS

Ninety-three HHT1 patients and 250 HHT2 patients were included. Epistaxis occurred later in HHT2, with incomplete penetrance (P<0.0001). Symptomatic PAVMs were more frequent in HHT1 (34.4 vs. 5.2%, P<0.001), as were cerebral abscesses (7.5 vs. 0.8%, P=0.002). Gastrointestinal bleeding occurred more frequently in HHT2 (16.4 vs. 6.5%, P=0.017). Symptomatic hepatic involvement was only seen in HHT2 patients. PAVMs were more frequently detected in asymptomatic HHT1 patients (54 vs. 12.8%, P<0.0001). PAVMs and HAVMs were often family clustered in HHT1 and HHT2, respectively. Truncating mutations were associated with a higher frequency of epistaxis and telangiectasis, in HHT2.

CONCLUSION

This study shows major differences between HHT1 and HHT2 phenotypes, which should be taken into account for future clinical studies.

Novel mutations in ENG and ACVRL1 identified in a series of 200 individuals undergoing clinical genetic testing for hereditary hemorrhagic telangiectasia (HHT): correlation of genotype with phenotype

Hereditary hemorrhagic telangiectasia (HHT; Osler-Weber-Rendu disease) is an autosomal dominant disease characterized by arteriovenous malformations ranging from cutaneous and mucous membrane telangiectasias to more severe pulmonary, gastrointestinal, and cerebral arteriovenous malformations (AVMs). Acute complications from bleeding or pulmonary shunting may be catastrophic. However, when diagnosed early, the complications can usually be prevented. Mutations in two genes, Endoglin (ENG) and activin receptor-like kinase 1 (ACVRL1 or ALK1) have been associated with HHT. We describe the results of mutation analysis on a consecutive series of 200 individuals undergoing clinical genetic testing for HHT. The observed sensitivity of mutation detection was similar to that in other series with strict ascertainment criteria. A total of 127 probands were found, with sequence changes consisting of 103 unique alterations, 68 of which were novel. In addition, eight intragenic rearrangements in the ENG gene and two in the ACVRL1 gene were identified in a subset of coding sequence mutation-negative individuals. Most individuals tested could be categorized by the number of HHT diagnostic criteria present. Surprisingly, almost 50% of the cases with a single symptom were found to have a significant sequence alteration; three of these reported only nosebleeds. Genetic testing can confirm the clinical diagnosis in individuals and identify presymptomatic mutation carriers. As many of the complications of HHT disease can be prevented, a confirmed molecular diagnosis provides an opportunity for early detection of AVMs and management of the disease.

Association of a polymorphism of the ACVRL1 gene with sporadic arteriovenous malformations of the central nervous system

OBJECT

Important central nervous system (CNS) manifestations in patients with hereditary hemorrhagic telangiectasia (HHT) include arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). Hereditary hemorrhagic telangiectasia is caused by germline mutations of two genes: ENG (HHT Type 1) and ACVRL1 (HHT Type 2). The ENG gene variations have been associated with the formation of intracranial aneurysms. The authors studied whether sequence variations in ACVRL1 or ENG are associated with the development of clinically sporadic arteriovenous dysplasias and aneurysms of the CNS.

METHODS

The coding sequence (in 44 patients with AVMs and 27 with aneurysms) and the 5' end and the polyA site (in 53 patients with AVMs) of the ACVRL1 gene were analyzed for sequence variations using direct sequencing and single-strand conformational polymorphism analysis. One ENG and three ACVRL1 gene polymorphisms were genotyped using restriction enzyme-based analysis in 101 patients with sporadic AVMs and DAVFs of the CNS, 79 patients treated for intracranial aneurysms, and 202 control volunteers. The authors identified a statistically significant association between the IVS3 -35A/T polymorphism in intron 3 of the ACVRL1 gene and the development of AVMs and DAVFs (p = 0.004; odds ratio [OR] 1.73; 95% confidence interval [CI] 1.19-2.51; after adjustments for age and sex), but not aneurysms (crude OR 0.82; 95% CI 0.55-1.18).

CONCLUSIONS

The results of this study link ACVRL1 (HHT Type 2 gene) to the formation of the clinically sporadic variants of vascular malformations of the CNS most commonly seen in patients with HHT, that is, AVMs and DAVFs.

Screening for children from families with Rendu-Osler-Weber disease: from geneticist to clinician

BACKGROUND

Rendu-Osler-Weber syndrome, or hereditary hemorrhagic telangiectasia (HHT), is an autosomal dominant vascular disorder. The syndrome is characterized by telangiectases and arteriovenous malformations (AVMs) affecting skin, mucosae and internal organs. AVMs often remain clinically silent until provoking sudden serious complications, responsible for important morbidity and mortality which can occur both in adulthood and in children. The incidence of AVMs in HHT pediatric populations is unknown.

OBJECTIVE

To describe the screening protocol performed in the first genotypically confirmed HHT pediatric population and to estimate the incidence of occult brain, lung and liver AVMs and the different disease phenotypes.

MATERIALS AND METHODS

Molecular analysis was performed on 35 children, both symptomatic and asymptomatic, who were family members of probands with a previously identified mutation. Clinical-instrumental examination was performed on the mutation positive cases. Nasal telangiectases were investigated by anterior rhinoscopy. Contrast echocardiography and high resolution thoracic multislice computed tomography (CT) were performed to detect pulmonary arteriovenous malformations (PAVMs), and echo-color Doppler, and abdominal CT to detect hepatic arteriovenous malformations (HAVMs). Brain magnetic resonance imaging was utilized to detect cerebral angiopathic involvement.

RESULTS

Molecular analysis demonstrated the mutation-carrier status in 22/35 children. Nineteen children, 12 of whom had epistaxis, positive to molecular testing underwent clinical evaluation. Nasal teleangiectases were found in 68%, mucocutaneous telangiectases (fingers, lips and oral cavity) in 79%, PAVMs in 53%, HAVMs in 47% and cerebral anteriovenous malformations and/or cerebral ischemic changes secondary to PAVMs in 12%.

CONCLUSIONS

We evidenced a high incidence of HHT children with occult visceral lesions suggesting that a diagnostic screening may be indicated to appropriately treat brain and lung malformations.

Mutation analysis in hereditary haemorrhagic telangiectasia in Germany reveals 11 novel ENG and 12 novel ACVRL1/ALK1 mutations

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal-dominant disease characterized by recurrent epistaxis, mucocutaneous telangiectasias and visceral arteriovenous malformations. Mutations in endoglin (ENG) and activin A receptor type II-like kinase 1 (ACVRL1 or ALK1) have been found in patients with HHT. We have screened a total of 51 unselected German index cases with the suspected diagnosis of HHT. We identified 30 different mutations in 32 cases (62.7%) by direct sequencing. Among these mutations, 11 of 13 ENG mutations and 12 of 17 ACVRL1 mutations were not previously reported in the literature. Two of the ACVRL1 mutations were each shared by two families. An analysis of the genotype-phenotype correlation is consistent with a more common frequency of pulmonary arteriovenous malformations in patients with ENG mutations than in patients with ACVRL1 mutations in our collective.

Hereditary hemorrhagic telangiectasia, a vascular dysplasia affecting the TGF-beta signaling pathway

Hereditary hemorrhagic telangiectasia (HHT) is caused by mutations in endoglin (ENG; HHT1) or ACVRL1/ALK1 (HHT2) genes and is an autosomal dominant vascular dysplasia. Clinically, HHT is characterized by epistaxis, telangiectases and arteriovenous malformations in some internal organs such as the lung, brain or liver. Endoglin and ALK1 proteins are specific endothelial receptors of the transforming growth factor (TGF)-beta superfamily that are essential for vascular integrity. Genetic studies in mice and humans have revealed the pivotal role of TGF-beta signaling during angiogenesis. Through binding to the TGF-beta type II receptor, TGF-beta can activate two distinct type I receptors (ALK1 and ALK5) in endothelial cells, each one leading to opposite effects on endothelial cell proliferation and migration. The recent isolation and characterization of circulating endothelial cells from HHT patients has revealed a decreased endoglin expression, impaired ALK1- and ALK5-dependent TGF-beta signaling, disorganized cytoskeleton and the failure to form cord-like structures which may lead to the fragility of small vessels with bleeding characteristic of HHT vascular dysplasia or to disrupted and abnormal angiogenesis after injuries and may explain the clinical symptoms associated with this disease.

External cervical root resorption involving multiple maxillary teeth in a patient with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an inherited syndrome characterized by mucocutaneous telangiectases that commonly involve the tongue, lips, fingers, and conjunctiva. While root resorption has been reported in association with central hemangiomas of bone, the association of HHT with external cervical root resorption has not been described to date. We report a case of a 57-year-old female with HTT who presented with advanced cervical root resorption involving multiple maxillary anterior teeth. Histologic examination of the gingival tissue adjacent to the area of root resorption demonstrated multiple thin-walled vascular elements as well as larger vascular channels surrounded by a thickened muscular layer. We hypothesize that the external root resorption seen in this case is the result of the HHT-related vascular process in the adjacent gingival tissue.

Epistaxis in patients with hereditary hemorrhagic teleangiectasia

Introduction. Spontaneous recurrent epistaxis is the most common clinical manifestation of hereditary hemorrhagic teleangiectasia (HHT). It occurs in more than 90% of HHT patients and is the most distressing symptom. Nasal teleangiectasias tend to increase with age both in size and number, so epistaxis is heavier and more frequent. For patients with mild to moderate disease, there are many adequate treatment options. For those with severe disease, most treatments offer just a hemorrhage-free interval. Experienced otorhinolaryngologists who treat epistaxis in these patients often use the adage "to do as little as possible for as long as possible". Management of acute epistaxis. The recommendations for the management of acute epistaxis include: compression, use of topical antifibrinolytics, laser therapy, argon plasma coagulation therapy, fibrin sealant spray or gelatin sponge soaked in adrenaline. In cases of heavy acute epistaxis, an epistaxis balloon combined with artery ligation and/or embolization is the most effective treatment. Nasal packing and electrocauterisation should be avoided to prevent further trauma to the blood vessels. Treatment of recurrent epistaxis. Management of recurrent epistaxis includes topical application of laser energy (argon, Nd: YAG, KTP/532 and diode, not CO2), argon plasma coagulation in combination with 0.1% estriol ointment, caustics, antifibrinolytics, bleomycin and sclerosing substances. Systemic estrogen-progesterone at doses used for oral contraception may eliminate bleeding in women with heavy epistaxis. Systemic antifibrinolitics (used with extreme precaution) and septal dermoplasty give good results. The only method which successfully and permanently solves the problem of severe refractory epistaxis in hereditary hemorrhagic teleangiectasia is closure of the nasal cavities. .

Telangiectasia hemorrágica hereditária: ácido tranexâmico no tratamento de úlcera plantar

Relato de um caso de úlcera plantar por fístula arteriovenosa em paciente portador de telangiectasia hemorrágica hereditária ou doença de Rendu-Osler-Weber tratado com ácido tranexâmico. Este fármaco é utilizado para tratamento de epistaxe, referindo-se o principal achado deste artigo ao uso eficaz desse medicamento na terapia de úlceras plantares hemorrágicas. São descritos os aspectos fisiopatológicos e clínicos da doença e as propriedades antifibrinolíticas do ácido tranexâmico. Este foi bem tolerado e apresentou evidências de eficácia na utilização para controle do sangramento e cicatrização da úlcera.