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BACKGROUND: Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for organ vascular malformations including arteriovenous malformations (AVMs) in the brain and lungs. North American HHT Centers of Excellence (CoEs) routinely screen for brain and lung AVMs, with the primary goal of detecting AVMs which can be treated before complications arise. Current international HHT guidelines provide recommendations for initial screening for brain and lung AVMs among children and adults with the disease, but rescreening recommendations are not comprehensively addressed and have not been reported. We determined current rescreening practices for brain and lung AVMs for children and adults with HHT among North American HHT CoEs. METHODS: We surveyed North American HHT CoEs regarding rescreening practices for new brain and lung AVMs in children and adults with initial negative screening. RESULTS: All thirty CoEs responded; 28 regarding pediatric (93.3%) and 30 (100%) regarding adult HHT care. The median duration of practice experience in HHT was 11.5 (range 3-30) years for providers of pediatric HHT care and 11.5 (range 3-35) years for providers of adult HHT care. The median number of patients followed at each CoE was 60 for children (range 8-500) and 375 for adults (range 30-1500). 25/28 CoEs (89.3%) reported rescreening children for brain AVMs, most commonly with enhanced MRI (21/25, 84%). 25 CoEs rescreen children for lung AVMs, most commonly every 5 years (15/25). Only 4/30 CoEs (13.3%) rescreen adults for brain AVMs. 26/30 CoEs (86.7%) reported rescreening adults for lung AVMs, most commonly every 5 years (18/26, 69.2%). CONCLUSIONS: Most HHT CoEs routinely rescreen children for brain and lung AVMs and adults for lung AVMs when initial screening is negative, but adults are infrequently rescreened for brain AVMs. Long-term data regarding risk for new brain and lung AVMs are required to establish practice guidelines for rescreening.

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by vascular malformations, including Pulmonary Arteriovenous Malformations (PAVMs), which can lead to serious complications such as dyspnea and hemorrhage. This report features a 37-year-old woman with HHT and multiple PAVMs. The diagnosis was established through physical examination, laboratory tests, and thoracic multislice computed tomography (MSCT). A hybrid management approach was applied, including embolization and thoracotomy. The patient underwent successful embolization of the inferior segment, followed by thoracotomy to overcome procedural difficulties. After the intervention, the patient's symptoms improved significantly, with no recurrence. Management of complex PAVMs may require a combination of methods, including embolization and surgery. The importance of early detection and adaptive management in HHT patients is expressed, given the high risk of complications. Embolization is the primary treatment for PAVMs, but in complex cases, surgical intervention is required. This study emphasizes the importance of a hybrid management approach and early detection in preventing serious complications in HHT patients, as well as the need for the development of better clinical guidelines for the management of PAVMs. [ABSTRACT FROM AUTHOR]

Introduction and purpose: Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare and complex vascular disorder characterized by abnormal blood vessel formation. It can present significant challenges in diagnosis and management, as it is currently estimated up to 90% of those affected are never diagnosed. Despite its rarity, HHT can carry substantial implications for patients and their families, at times requiring comprehensive medical care and support. This paper aims to provide an in-depth exploration of HHT, encompassing its epidemiology, genetics, clinical manifestations, diagnostic approaches, and current management strategies. Moreover, we hope to point out possible areas in need of future research. Description of the state knowledge: HHT is an autosomal dominant genetic disorder that affects 1 in 5-10,000 people. Its most prominent symptoms include telangiectasia of skin and mucous membranes, recurrent epistaxis, gastrointestinal bleeding and arteriovenous malformations in vital organs. In the vast majority of cases, it is caused by a mutation in one of the following genes: ENG, ACVRL1, SMAD4; however, mutations in other genes have been described to cause a similar or much the same constellation of symptoms. Treatment options are focused on managing symptoms and improving quality of life, but possible new treatment options are being researched that could change the landscape of HHT management. Summary: HHT is a severely underdiagnosed disease that has seen a surge of researchers’ interest in recent years. We firmly believe that, combined with plummeting costs of genetic testing and possible new treatment options, means that HHT will become increasingly important in physicians’ everyday practice. [ABSTRACT FROM AUTHOR]

Telangiectases and arteriovenous malformations (AVMs) are the characteristic lesions of Hereditary Hemorrhagic Telangiectasia (HHT). Somatic second-hit loss-of-function variations in the HHT causative genes, ENG and ACVRL1, have been described in dermal telangiectasias. It is unclear if somatic second-hit mutations also cause the formation of AVMs and nasal telangiectasias in HHT. To investigate the genetic mechanism of AVM formation in HHT, we evaluated multiple affected tissues from fourteen individuals. DNA was extracted from fresh/frozen tissue of 15 nasal telangiectasia, 4 dermal telangiectasia, and 9 normal control tissue biopsies, from nine unrelated individuals with HHT. DNA from six formalin-fixed paraffin-embedded (FFPE) AVM tissues (brain, lung, liver, and gallbladder) from five individuals was evaluated. A 736 vascular malformation and cancer gene next-generation sequencing (NGS) panel was used to evaluate these tissues down to 1% somatic mosaicism. Somatic second-hit mutations were identified in three in four AVM biopsies (75%) or half of the FFPE (50%) samples, including the loss of heterozygosity in ENG in one brain AVM sample, in which the germline mutation occurred in a different allele than a nearby somatic mutation (both are loss-of-function mutations). Eight of nine (88.9%) patients in whom telangiectasia tissues were evaluated had a somatic mutation ranging from 0.68 to 1.96% in the same gene with the germline mutation. Six of fifteen (40%) nasal and two of four (50%) dermal telangiectasia had a detectable somatic second hit. Additional low-level somatic mutations in other genes were identified in several telangiectasias. This is the first report that nasal telangiectasias and solid organ AVMs in HHT are caused by very-low-level somatic biallelic second-hit mutations. [ABSTRACT FROM AUTHOR]

Interstitial Lung Disease (ILD) in diffuse cutaneous Systemic Sclerosis (SSc) patients is present in about 53% of cases and 35% in cases with limited cutaneous SSc. Even though there are only a few case reports of ILD associated with Hereditary Haemorrhagic Telangiectasia (HHT), a direct association of SSc and HHT has not been reported. Hence, little is known about the pathogenetic link between the two diseases. In this case report, a 24 years old married female patient presented with progressive breathlessness for one year. Initial evaluation of the patient suggested the diagnosis of SSc based on clinical findings like sclerodactyly along with telangiectasia. High Resolution Computed Tomography (HRCT) of the chest revealed the presence of pulmonary arteriovenous malformation along with ILD. Past medical history and family history of epistaxis for three generations suggested the diagnosis of HHT. This case reports a rare association of Connective Tissue Disease (CTD) and an autosomal disorder of vascular dysplasia with overlapping features of telangiectasia. This case is presented to highlight the possible association of HHT with CTDs. With the currently available literature, an attempt is made to find a plausible pathogenetic link between HHT and SSc. Transforming Growth Factor-β (TGF-β) is a pleiotropic growth factor that regulates the growth and differentiation of various cell types, and immune regulation has been implicated in the pathogenesis of both HHT and SSc. The other pathogenetic mechanism common to both diseases is impaired nitric oxide-mediated vasodilation. This case report emphasises the need for further research for a better understanding of the pathogenesis of both diseases. [ABSTRACT FROM AUTHOR]

This article discusses a rare condition called cutaneous collagenous vasculopathy (CCV), which is characterized by the gradual onset of widespread telangiectasias (dilated blood vessels). The condition primarily affects middle-aged females, but there have been only three documented cases in pediatric patients. The article presents a fourth case of pediatric CCV and reviews the features that distinguish it from other similar presentations of telangiectasias. The diagnosis of CCV relies on histology with collagen-specific immunostaining. The etiology of CCV is unclear, but it is postulated that genetic anomalies, underlying systemic diseases, and pharmacologic triggers may play a role. The treatment for CCV is primarily cosmetic, with options such as pulsed dye laser or optimized pulsed light. Further studies are needed to evaluate treatment in both adult and pediatric populations. [Extracted from the article]

Background: Osler-Weber-Rendu syndrome (OWRS) is an autosomal dominant disease with recurrent epistaxis, mucocutaneous telangiectasias, and arteriovenous malformations. Its clinical presentation ranges from simple skin lesions to life-threatening complications. When the diagnosis of the disease is delayed, it can be mortal and have high morbidity. This case is presented because OWRS is rare, and although she has all the features of the disease, she was diagnosed in the geriatric age group. Case presentation: A 72-year-old female patient who applied to the emergency department with the complaint of melena was diagnosed with upper gastrointestinal system bleeding. Gastroscopy revealed angiodysplasia in the bulb. Colonoscopy was normal. She had telangiectasias on her face, maxilla, nose, tongue and lips. She also had recurrent epistaxis and a family history. Thorax CT showed aneurysmatic vascular malformations in the lung. Abdominal MRI revealed vascular malformations in the liver. Brain MRI was normal. The patient was diagnosed with OWRS according to the Curaçao diagnostic criteria because of telangiectasia in the mouth, nose, and face, angiodysplasia in the gastric bulb, aneurysmatic vascular dilatation in the lung, vascular pathologies in the liver, and a history of epistaxis and telangiectasia in the patient's family members. Conclusion: This patient is presented because OWRS is rare, and although she has all the features of the disease, she was diagnosed in the geriatric age group. Clinicians should be aware of this rare disease. Especially in the elderly, when angiodysplasia causing gastrointestinal bleeding is detected, it should be considered in the differential diagnosis that this may be an OWSR case. [ABSTRACT FROM AUTHOR]

BackgroundRetrospective questionnaire and healthcare administrative data suggest reduced life expectancy in untreated hereditary hemorrhagic telangiectasia (HHT). Prospective data suggests similar mortality, to the general population, in Denmark's centre-treated HHT patients. However, clinical phenotypes vary widely in HHT, likely affecting mortality. We aimed to measure predictors of mortality among centre-treated HHT patients. HHT patients were recruited at 14 HHT centres of the Brain Vascular Malformation Consortium (BVMC) since 2010 and followed annually. Vital status, organ vascular malformations (VMs) and clinical symptoms data were collected at baseline and during follow-up (N = 1286). We tested whether organ VMs, HHT symptoms and HHT genes were associated with increased mortality using Cox regression analysis, adjusting for patient age, sex, and smoking status.Results59 deaths occurred over average follow-up time of 3.4 years (max 8.6 years). A history of anemia was associated with increased mortality (HR = 2.93, 95% CI 1.37-6.26, p = 0.006), as were gastro-intestinal (GI) bleeding (HR = 2.63, 95% CI 1.46-4.74, p = 0.001), and symptomatic liver VMs (HR = 2.10, 95% CI 1.15-3.84, p = 0.015). Brain VMs and pulmonary arteriovenous malformations (AVMs) were not associated with mortality (p > 0.05). Patients with SMAD4 mutation had significantly higher mortality (HR = 18.36, 95% CI 5.60-60.20, p

BackgroundHepatic arteriovenous malformations (AVMs) in hereditary hemorrhagic telangiectasia (HHT) patients are most commonly hepatic artery to hepatic venous shunts which can result in high-output heart failure. This condition can be debilitating and is a leading cause of liver transplantation in HHT patients. However, it is not known what characteristics can discriminate between asymptomatic patients and those who will develop heart failure symptoms.Results176 patients with HHT were evaluated with computed tomography angiography (CTA) between April 2004 and February 2019 at our HHT Center of Excellence. 63/176 (35.8%) patients were found to have hepatic AVMs on CTA. 18 of these patients were excluded because of the presence of another condition which could confound evaluation of heart failure symptoms. In the remaining 45 patients included in our cohort, 25/45 (55.6%) patients were classified as asymptomatic and 20/45 (44.4%) were classified as symptomatic, and these groups were compared. In symptomatic patients, mean common hepatic artery (CHA) diameter was significantly higher (11.1 versus 8.4 mm) and mean hemoglobin levels were significantly lower (10.7 vs 12.6 g/dL). A stepwise multiple logistic regression analysis demonstrated that both CHA diameter and hemoglobin level were independent predictors of heart failure symptoms with ORs of 2.554 (95% CI 1.372-4.754) and 0.489 (95% CI 0.299-0.799), respectively. The receiver operator characteristic (ROC) curve of our analysis demonstrated an AUC of 0.906 (95% CI 0.816-0.996), sensitivity 80.0% (95% CI 55.7-93.4%), and specificity 75.0% (95% CI 52.9-89.4%).ConclusionsCTA is an effective and easily reproducible method to evaluate hepatic involvement of HHT. Utilizing CTA, clinical, and laboratory data we determined CHA diameter and hemoglobin level were independent predictors of heart failure symptoms.

Introduction and purpose: Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare and complex vascular disorder characterized by abnormal blood vessel formation. It can present significant challenges in diagnosis and management, as it is currently estimated up to 90% of those affected are never diagnosed. Despite its rarity, HHT can carry substantial implications for patients and their families, at times requiring comprehensive medical care and support. This paper aims to provide an in-depth exploration of HHT, encompassing its epidemiology, genetics, clinical manifestations, diagnostic approaches, and current management strategies. Moreover, we hope to point out possible areas in need of future research. Description of the state knowledge: HHT is an autosomal dominant genetic disorder that affects 1 in 5-10,000 people. Its most prominent symptoms include telangiectasia of skin and mucous membranes, recurrent epistaxis, gastrointestinal bleeding and arteriovenous malformations in vital organs. In the vast majority of cases, it is caused by a mutation in one of the following genes: ENG, ACVRL1, SMAD4; however, mutations in other genes have been described to cause a similar or much the same constellation of symptoms. Treatment options are focused on managing symptoms and improving quality of life, but possible new treatment options are being researched that could change the landscape of HHT management. Summary: HHT is a severely underdiagnosed disease that has seen a surge of researchers’ interest in recent years. We firmly believe that, combined with plummeting costs of genetic testing and possible new treatment options, means that HHT will become increasingly important in physicians’ everyday practice.

Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu–Osler–Weber syndrome, is a vascular disorder of autosomal dominant etiology. The hallmark clinical feature is the presence of recurrent episodes of epistaxis in patients with vascular malformations and a tendency to bleed. We present the case of a 71-year-old woman who presented to the emergency department with upper gastrointestinal bleeding caused by esophageal varices, in conjunction with gastric angiodysplasias. The presence of oronasopharyngeal telangiectasias and hepatomegaly raised suspicion of HHT. The diagnostic workup confirmed the presence of angiodysplasia in the gastric region, portal arteriovenous malformation, and a pulmonary shunt. [ABSTRACT FROM AUTHOR]

Objective: Brain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date. Methods: We identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM. Results: Most patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08–0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I–II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25–44.4) and 20 (IQR 18–22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17–39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC. Conclusions: Patients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs. [ABSTRACT FROM AUTHOR]

This article discusses the potential use of the MEK inhibitor trametinib as a treatment for hereditary haemorrhagic telangiectasia (HHT), a condition characterized by vascular malformations. The study presents a clinical case of a patient with HHT who experienced a reduction in nosebleeds and transfusion requirements after taking trametinib. The authors also provide RNA sequencing data from blood outgrowth endothelial cells (BOECs) derived from HHT patients, which suggest that MEK1 inhibition may be beneficial in reducing HHT-associated bleeding and anemia. Further research is needed to confirm these findings and optimize dosing regimens. [Extracted from the article]

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. [ABSTRACT FROM AUTHOR]

Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disease characterized by recurrent epistaxis, mucocutaneous telangiectasias, and visceral arteriovenous malformations. Multiple genetic mutations have been linked to this rare disease, including ENG, ALK1 (ACVRL1), and MADH4. Pulmonary hypertension is a potential complication of HHT, with the most common phenotypes being World Health Organization (WHO) group 1 heritable pulmonary arterial hypertension (PAH), which is typically associated with ALK1 mutation; WHO group 2 pulmonary hypertension due to high output heart failure from hepatic arteriovenous malformations and/or anemia; and WHO group 2 due to high pulmonary artery wedge pressure. There is scarce evidence to help guide treatment of heritable PAH in HHT, and observational literature suggests that patients with HHT and heritable PAH have a worse prognosis compared to patients with idiopathic PAH. We describe the diagnosis, pulmonary hemodynamics, and detailed treatment courses of three patients with ALK1-associated HHT and PAH, who all exhibited objective clinical improvement with parenteral prostacyclins and oral agents. [ABSTRACT FROM AUTHOR]

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterised by vascular dysplasia. Hepatic vascular m alformations (VMs) range from small telangiectases to significant vascular shunting. Here we report two cases of HHT. Case 1 had diffuse ectasia of the hepatic artery along its intrahepatic and extrahepatic course with a hepatic arterial aneurysm. Case 2 presented with ileal and hepatic telangiectases. Knowledge of these vascular variants is indispensable for clinicians and radiologists in aiding diagnosis and surgical and interventional management. [ABSTRACT FROM AUTHOR]

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant hereditary disorder characterized by recurrent spontaneous epistaxis, mucocutaneous telangiectasias, and solid organ arteriovenous malformations (AVMs). Pulmonary hypertension (PH) is an increasingly recognized complication in patients with HHT, most often precipitated by high-output heart failure in the presence of hepatic AVMs as well as pulmonary arterial hypertension in the form of a proliferative vasculopathy. The presence of PH in patients with HHT is associated with significant elevations in rates of morbidity and mortality. Additionally, there is growing recognition of a thromboembolic propensity in this population that increases the risk of chronic thromboembolic PH, posing unique clinical considerations regarding the use of anticoagulation. Patients with HHT are also at risk of PH due to disorders commonly seen in the general population, including left-sided heart and lung disease. The etiology of PH in HHT is multifaceted and complex; the diagnostic approach and treatment strategies must consider the underlying pathophysiology of HHT. This comprehensive review summarizes current knowledge of PH in HHT, detailing the pathogenesis of known etiologies, diagnostic evaluation, and suggested treatment modalities as well as emerging therapies that may be of future interest. [ABSTRACT FROM AUTHOR]

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant vascular disorder characterized by small, dilated clustered vessels (telangiectasias) and by larger visceral arteriovenous malformations (AVMs), which directly connect the feeding arteries with the draining veins. These lesions are fragile, prone to rupture, and lead to recurrent epistaxis and/or internal hemorrhage among other complications. Germline heterozygous loss-of-function (LOF) mutations in Bone Morphogenic Protein 9 (BMP9) and BMP10 signaling pathway genes (endoglin-ENG, activin like kinase 1 ACVRL1 aka ALK1, and SMAD4) cause different subtypes of HHT (HHT1, HHT2 and HHT-juvenile polyposis (JP)) and have a worldwide combined incidence of about 1:5000. Expert clinicians and international scientists gathered in Cascais, Portugal from September 29th to October 2nd, 2022 to present the latest scientific research in the HHT field and novel treatment strategies for people living with HHT. During the largest HHT scientific conference yet, participants included 293 in person and 46 virtually. An impressive 209 abstracts were accepted to the meeting and 59 were selected for oral presentations. The remaining 150 abstracts were presented during judged poster sessions. This review article summarizes the basic and clinical abstracts selected as oral presentations with their new observations and discoveries as well as surrounding discussion and debate. Two discussion-based workshops were also held during the conference, each focusing on mechanisms and clinical perspectives in either AVM formation and progression or current and future therapies for HHT. Our hope is that this paper will represent the current progress and the remaining unanswered questions surrounding HHT, in order to serve as an update for those within the field and an invitation to those scientists and clinicians as yet outside of the field of HHT. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease, causes recurrent mucous membrane hemorrhage, especially epistaxis. In this systematic review, we discuss the efficacies of the three most common laser photocoagulation treatments for HHT-related epistaxis. STUDY DESIGN/MATERIALS AND METHODS: A systematic literature search was conducted in PubMed and MEDLINE from database inception to March 2019. Studies reporting epistaxis outcomes following argon, neodymium-doped yttrium aluminum garnet (Nd:YAG), and diode laser photocoagulation for HHT were included. χ2 and Barnards exact tests were utilized to detect differences in reduced epistaxis frequency and intensity rates. RESULTS: Fifteen out of 157 published studies met our eligibility criteria, spanning a collective 362 patients. Argon, Nd:YAG, and diode laser therapy reduced epistaxis frequency in 90.4%, 88.9%, and 71.1% of patients, respectively, and reduced epistaxis intensity in 87.8%, 87.2%, and 71.1% of patients, respectively. Diode laser photocoagulation significantly underperformed in both outcome measurements when compared with argon (frequency: P = 0.005; intensity: P = 0.034) and Nd:YAG (frequency: P = 0.012; intensity: P = 0.041). There was no significant difference between argon and Nd:YAG in reducing HHT epistaxis frequency (P = 0.434) or intensity (P = 0.969). Categorizing HHT patients by clinical severity demonstrated a higher rate of improvement in the mild-moderate group compared with the severe group in both argon (P

Patient-derived induced pluripotent stem cells (iPSCs) provide a powerful tool for identifying cellular and molecular mechanisms of disease. Macular telangiectasia type 2 (MacTel) is a rare, late-onset degenerative retinal disease with an extremely heterogeneous genetic architecture, lending itself to the use of iPSCs. Whole-exome sequencing screens and pedigree analyses have identified rare causative mutations that account for less than 5% of cases. Metabolomic surveys of patient populations and GWAS have linked MacTel to decreased circulating levels of serine and elevated levels of neurotoxic 1-deoxysphingolipids (1-dSLs). However, retina-specific, disease-contributing factors have yet to be identified. Here, we used iPSC-differentiated retinal pigmented epithelial (iRPE) cells derived from donors with or without MacTel to screen for novel cell-intrinsic pathological mechanisms. We show that MacTel iRPE cells mimicked the low serine levels observed in serum from patients with MacTel. Through RNA-Seq and gene set enrichment pathway analysis, we determined that MacTel iRPE cells are enriched in cellular stress pathways and dysregulation of central carbon metabolism. Using respirometry and mitochondrial stress testing, we functionally validated that MacTel iRPE cells had a reduction in mitochondrial function that was independent of defects in serine biosynthesis and 1-dSL accumulation. Thus, we identified phenotypes that may constitute alternative disease mechanisms beyond the known serine/sphingolipid pathway. [ABSTRACT FROM AUTHOR]

Purpose of reviewThe TGFβ (transforming growth factor β) superfamily - a large group of structurally related and evolutionarily conserved proteins - profoundly shapes and organizes the vasculature during normal development and adult homeostasis. Mutations inactivating several of its ligands, receptors, or signal transducers set off hereditary hemorrhagic telangiectasia (HHT), a disorder that causes capillary networks to form incorrectly. Drosha, an essential microRNA-processing enzyme, also interfaces with TGFβ signal transducers, but its involvement in vascular conditions had not been tested until recently. This review summarizes current evidence that links mutations of Drosha to HHT.Recent findingsGenetic studies have revealed that rare missense mutations in the Drosha gene occur more commonly among HHT patients than in healthy people. Molecular analyses also indicated that Drosha enzymes with HHT-associated mutations generate microRNAs less efficiently than their wild-type counterpart when stimulated by TGFβ ligands. In zebrafish or mouse, mutant Drosha proteins cause the formation of dilated, leaky blood vessels deprived of capillaries, similar to those typically found in patients with HHT.SummaryRecent evidence suggests that Drosha-mediated microRNA biogenesis contributes significantly to the control of vascular development and homeostasis by TGFβ. Loss or reduction of Drosha function may predispose carriers to HHT and possibly other vascular diseases.

Hereditary haemorrhagic telangiectasia, also known as Rendu–Osler–Weber disease, is an autosomal dominant disorder of the fibrovascular tissue common in Western countries. It is characterized by the classical triad of mucocutaneous telangiectasia, arteriovenous malformations with recurrent epistaxis. Here we report a rare case of Hereditary haemorrhagic telangiectasia in a 66-year-old Indian male who presented with a history of recurrent epistaxis of forty years duration. The nasal telangiectasias were ablated under narrow band imaging guidance. The rarity of diagnosis was aided by clinical exome sequencing to confirm the disease. [ABSTRACT FROM AUTHOR]

Objective: Rare disease. Background: Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant genetic disease associated with arteriovenous malformations involving diverse organs. Neurological complications from brain abscesses (BA) secondary to pulmonary arteriovenous malformations (PAVMs) is a serious and recognized, albeit infrequent, medical problem. We report the case of a 37-year-old man with familial HHT and PAVMs who presented with seizures as a manifestation of BA. Case Report: A 37-year-old man was admitted for first tonic-clonic seizures. He had a history of recurrent epistaxis and recurrent gastrointestinal bleeds treated with fulguration and oral iron therapy. A diagnosis of HHT was made because the patient met 3 of 4 Curaçao criteria. Physical examination revealed hypoxemia without dyspnea. A chest X-ray detected nodular pulmonary lesions in both lower lobes. Cranial computed tomography (CT) revealed 3 space-occupying lesions. Antiepileptics and dexamethasone were started. Cranial magnetic resonance and positron emission tomography suggested that lesions were BA. Thoracoabdominal CT with contrast revealed several bilateral PAVMs. Blood cultures were repeatedly negative. With the presumptive diagnosis of septic-embolic BA, empirical antibiotic therapy was started for 8 weeks. Neurological symptoms resolved and malformations >2 cm were selectively embolized. A genetic study revealed exon5 mutations in the ENG gene. Conclusions: This report highlights the association between PAVMs in a patient with HHT and development of BA. Clinicians should be aware of this association so that diagnosis and treatment can be provided as fast as possible to ensure the best outcome for the patient. Embolization was performed as preventive treatment, and a genetic study was conducted as it is potentially useful for primary prevention in the patient's offspring. [ABSTRACT FROM AUTHOR]

Objective: To retrospectively describe a large series of pregnancies in women with hereditary haemorrhagic telangiectasia followed in our reference centre, plus neonatal outcomes, to better understand the risks of complications and to improve their prevention. Design: A retrospective descriptive study conducted through a phone questionnaire. Setting: Reference centre for hereditary haemorrhagic telangiectasia in Lyon, France. Population: Women meeting the following criteria: (1) alive and aged ≥18 years; (2) with a definite clinical and/or genetic diagnosis of hereditary haemorrhagic telangiectasia; and (3) with at least one full‐term pregnancy. Main outcome measures: Maternal and perinatal outcomes of pregnancies in women with hereditary haemorrhagic telangiectasia. Results: Five hundred and sixty‐two pregnancies were reported in 207 women with hereditary haemorrhagic telangiectasia. A total of 271 complications (48.2%) were registered. Of these, 149 (55%) non‐specific complications, 110 (40.6%) non‐severe specific complications and 12 (4.4%) severe specific complications were registered. There were four cases of haemoptysis and two cases of transient ischaemic attack related to pulmonary arteriovenous malformations. Four patients had severe decompensated dyspnoea, related to pulmonary arteriovenous malformations in three cases and to pulmonary arteriovenous malformations associated with severe hepatic arteriovenous malformations in one case. Hepatobiliary necrosis occurred in one case. Epidural or spinal anaesthesia was performed in 139 of 452 deliveries (31%), without complications. There were 12 reports of congenital anomalies in 461 live births (3%). Conclusions: Most pregnancies in hereditary haemorrhagic telangiectasia women are uneventful; complications are rare but can be severe. Women thus need to be educated about screening and possible pregnancy‐related risks before becoming pregnant. [ABSTRACT FROM AUTHOR]

Arteriovenous malformations (AVMs) are abnormal connections of vessels that shunt blood directly from arteries into veins. Rupture of brain AVMs (bAVMs) can cause life-threatening intracranial bleeding. Even though the majority of bAVM cases are sporadic without a family history, some cases are familial. Most of the familial cases of bAVMs are associated with a genetic disorder called hereditary hemorrhagic telangiectasia (HHT). The mechanism of bAVM formation is not fully understood. The most important advances in bAVM basic science research is the identification of somatic mutations of genes in RAS-MAPK pathways. However, the mechanisms by which mutations of these genes lead to AVM formation are largely unknown. In this review, we summarized the latest advance in bAVM studies and discussed some pathways that play important roles in bAVM pathogenesis. We also discussed the therapeutic implications of these pathways.

BackgroundHereditary hemorrhagic telangiectasia (HHT) is caused by mutations in TGFβ/BMP9 pathway genes and characterized by vascular malformations (VM) including arteriovenous malformations (AVM) in lung, liver, and brain, which lead to severe complications including intracranial hemorrhage (ICH) from brain VM. The clinical heterogeneity of HHT suggests a role for genetic modifier effects. Common variants in loci that modify phenotype severity in Tgfb knockout mice were previously reported as associated with lung AVM in HHT. Common variants in candidate genes were reported as associated with sporadic brain AVM and/or ICH. We investigated whether these variants are associated with HHT organ VM or with ICH from brain VM in 752 Caucasian HHT patients enrolled by the Brian Vascular Malformation Consortium.MethodsWe genotyped 11 candidate variants: four variants reported as associated with lung AVM in HHT (PTPN14 rs2936018, USH2A rs700024, ADAM17 rs12474540, rs10495565), and seven variants reported as associated with sporadic BAVM or ICH (APOE ε2, ANGPTL4 rs11672433, EPHB4 rs314308, IL6 rs1800795, IL1B rs1143627, ITGB8 rs10486391, TNFA rs361525). Association of genotype with any VM, lung AVM, liver VM, brain VM or brain VM ICH was evaluated by multivariate logistic regression adjusted for age, gender, and family clustering.ResultsNone of the 11 variants was significantly associated with any phenotype. There was a trend toward association of USH2A rs700024 with ICH (OR = 2.77, 95% CI = 1.13-6.80, p = .026).ConclusionWe did not replicate previously reported associations with HHT lung AVM and variants in Tgfb modifier loci. We also did not find significant associations between variants reported in sporadic brain AVM and VM or ICH in HHT.

Hereditary hemorrhagic telangiectasis (HHT) is an autosomal dominant hereditary disease, which can lead to abnormal angiogenesis. We performed contrast-enhanced ultrasound (CEUS) in a patient with HHT represented with hemothorax. After targeted embolization, the condition of hemothorax improved. In this case, we explore the use of CEUS to locate the responsible vessel of hemothorax, and found that CEUS could be used as a complementary preoperative method of localization with computed tomography angiography (CTA). [ABSTRACT FROM AUTHOR]

Hereditary hemorrhagic telangiectasis (HHT) and juvenile polyposis syndrome (JPS) are both relatively rare hereditary disorders. It has been reported that patients with SMAD4 mutations may suffer from both HHT and JPS, defined as JPS/HHT. To improve the understanding and diagnosis of these diseases, we herein report a case of a 17-year-old male with abdominal pain and hematochezia. Low-tension computed tomography (CT) of the small intestine showed intussusception. Combined with the patient's medical history of nasal bleeding and pulmonary arteriovenous fistula (pAVF) embolism, a final diagnosis of JPS/HHT was reached, according to the Curaçao Diagnostic Criteria. The possibility of JPS/HHT should be considered in patients with epistaxis and intussusception. [ABSTRACT FROM AUTHOR]

Steroid 5α‐reductase type 3 congenital disorder of glycosylation (SRD5A3‐CDG) is an extremely rare congenital disease. Common manifestations are developmental delay, intellectual disability, ophthalmological abnormalities, cerebellar abnormalities, ataxia, and hypotonia. Here, we discuss a seven‐year‐old boy with SRD5A3‐CDG (homozygous variant c.57G>A [p.Trp19Ter]), featuring the unprecedented finding of telangiectasia. [ABSTRACT FROM AUTHOR]

Haploinsufficiency for Endoglin (ENG) and activin A receptor type II-like I (ACVRL1/ALK1) lead to the formation of weak and abnormal vessels in hereditary hemorrhagic telangiectasia (HHT). These cause epistaxis (nosebleeds) and/or gastrointestinal blood loss. In vitro in cultured endothelial cells, tacrolimus has been shown to increase ENG and ALK1 expression. It is, therefore, a potential treatment option. We report here a proof-of-concept study in patients with HHT and severe epistaxis and/or gastrointestinal bleeding who were treated daily with orally-administered tacrolimus for twenty weeks. Twenty-five patients with HHT (11 females (44%)) and median age of 59 years were enrolled. Five patients (20%) stopped the trial prematurely-four due to (serious) adverse events ((S)AE). Twenty patients were included in further analyses. Hemoglobin levels increased during tacrolimus treatment from 6.1 (IQR 5.2–6.9) mmol/L at baseline (9.8 g/dL) to 6.7 (6.5–7.1) mmol/L (10.8 g/dL), p = 0.003. The number of blood transfusions over the twenty weeks decreased from a mean of 5.0 (±9.2) to 1.9 (±3.5), p = 0.04. In 64% of the patients, at least one AE occurred. Oral tacrolimus, thus, significantly increased hemoglobin levels and decreased blood transfusion needs, epistaxis and/or gastrointestinal bleeding in patients with HHT. However, side-effects were common. Further investigation of the potential therapeutic benefit is justified by the outcome of the study. [ABSTRACT FROM AUTHOR]

A 62-year-old man presented with complaints of decreased vision in BE. His best-corrected visual acuity (BCVA) was 6/12 in both eyes (BE). Based on his fundus examination and imaging findings, he was diagnosed with BE Macular Telangiectasia type 2 (MacTel 2) and was advised of regular follow-up. Over the course of follow-up, he developed further reduction in vision in the right eye (RE) to 6/24. Spectral-domain optical coherence tomography (SD-OCT) showed the presence of a subfoveal detachment (SFD) with intraretinal cystoid edema. He was diagnosed to have an exudative variant of preproliferative MacTel 2 and underwent three intravitreal injections of bevacizumab in the RE following which there was an improvement in BCVA to 6/12 along with the complete resolution of SFD and IRF on SD-OCT. This report describes a rare case of exudative nonproliferative macular telangiectasia type 2 presenting with the presence of intraretinal fluid. [ABSTRACT FROM AUTHOR]

BackgroundCerebral arteriovenous malformations (AVMs) are common in patients with hereditary hemorrhagic telangiectasia (HHT). However, due to the rarity of HHT and little published evidence of outcomes from management of brain AVMs in this disease, current international HHT guidelines recommend an individualized approach. Specifically, the outcomes for surgical vs nonsurgical management of these lesions have not been reported to date.ObjectiveTo report long-term outcomes of surgical resection of brain AVMs in HHT patients compared to outcomes in nonsurgically treated patients.MethodsFrom the database of the Brain Vascular Malformation Consortium HHT project, 19 patients with 20 resected AVMs (group 1) and 22 patients with 33 AVMs who received nonsurgical treatment (group 2) were studied. The groups were retrospectively reviewed for changes in functional status (modified Rankin Scale score) during the follow-up period.ResultsDuring the follow-up period, 9% of patients in group 1 suffered from worsening of functional status, whereas this figure was 16% for group 2 (P > .05). Functional outcomes were not statistically different between the 2 groups at the latest follow-up (P > .05).ConclusionHHT patients treated surgically for brain AVMs appear to have long-term functional outcomes comparable to nonsurgical (including observational) therapy with fewer unfavorable outcomes. It is therefore reasonable to consider surgical resection as a management option in the multidisciplinary team's individualized treatment strategy for HHT patients with brain AVMs.