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.     

Hereditary hemorrhagic telangiectasia: an update on clinical manifestations and diagnostic measures

Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber disease, is an autosomal dominant disorder of the fibrovascular tissue. It is characterized by the classic triad of (muco-)cutaneous telangiectases, arteriovenous malformations with recurrent epistaxis and hemorrhages, and inheritance. A wide variety of clinical manifestations in HHT have been described. In more than 90% of the patients, nosebleeds are the first predominant symptom, therefore ENT physicians often play a key role as far as diagnosis and management of the disease are concerned. In spite of recent diagnostic and therapeutic progress, a cure for this often burdening and handicapping disease is still not available. Apart from affecting the nose, arteriovenous malformations (AVMs) may also affect the skin, lungs, brain, liver and gastrointestinal tract. The two known genes that are implicated in HHT are endoglin (ENG) located on chromosome 9q33-q34 and activin-receptor-like kinase (ALK1) located on chromosome 12q13. Mutations of ENG are observed in HHT type 1 with an incidence up to 40% for pulmonary AVMs, whereas mutations of ALK1 are observed in HHT type 2 with an incidence of only 14% for pulmonary AVMs, which clinically distinguishes these two types of mutation. The emphasis of this paper is mainly on the clinical manifestation, molecular genetics and diagnosis of HHT, taking account of current literature on HHT in order to better understand the complexity of the disease. Recent therapeutic options in the treatment of HHT have been omitted from this paper as they are subject of a following paper. HHT is more common than previously thought and shows a broad range of different clinical organ manifestations that can be sources of substantial morbidity and mortality, making HHT a continuing challenge for many sub-specialties where interdisciplinary diagnostic screening is mandatory in the management of the disease.     

Overview of Pulmonary Arteriovenous Malformations and Hereditary Hemorrhagic Telangiectasia

Pulmonary arteriovenous malformations (PAVMs) are rare and commonly caused by an autosomal dominant disorder known as hereditary hemorrhagic telangiectasia (HHT). HHT is an often-missed vascular disorder causing symptoms of epistaxis, mucosal telangiectasia, AVMs, hemoptysis, dyspnea, and iron deficiency anemia. Large AVMs in the lungs, liver, and brain can be life-threatening. Early diagnosis and intervention are imperative to prevent serious complications of massive hemoptysis, stroke, cerebral abscess, and gastrointestinal bleeding. This case study of an incidental finding of a PAVM on routine chest-ray proves to be a life-saving event for a young African American woman with undiagnosed HHT.     

Real-time imaging of de novo arteriovenous malformation in a mouse model of hereditary hemorrhagic telangiectasia

Arteriovenous malformations (AVMs) are vascular anomalies where arteries and veins are directly connected through a complex, tangled web of abnormal arteries and veins instead of a normal capillary network. AVMs in the brain, lung, and visceral organs, including the liver and gastrointestinal tract, result in considerable morbidity and mortality. AVMs are the underlying cause of three major clinical symptoms of a genetic vascular dysplasia termed hereditary hemorrhagic telangiectasia (HHT), which is characterized by recurrent nosebleeds, mucocutaneous telangiectases, and visceral AVMs and caused by mutations in one of several genes, including activin receptor–like kinase 1 (ALK1). It remains unknown why and how selective blood vessels form AVMs, and there have been technical limitations to observing the initial stages of AVM formation. Here we present in vivo evidence that physiological or environmental factors such as wounds in addition to the genetic ablation are required for Alk1-deficient vessels to develop to AVMs in adult mice. Using the dorsal skinfold window chamber system, we have demonstrated for what we believe to be the first time the entire course of AVM formation in subdermal blood vessels by using intravital bright-field images, hyperspectral imaging, fluorescence recordings of direct arterial flow through the AV shunts, and vascular casting techniques. We believe our data provide novel insights into the pathogenetic mechanisms of HHT and potential therapeutic approaches.     

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.     

Mutation analysis in Spanish patients with hereditary hemorrhagic telangiectasia: deficient endoglin up-regulation in activated monocytes

BACKGROUND: Mutations in the endoglin (ENG) or ALK1 genes are responsible for hereditary hemorrhagic telangiectasia types 1 and 2 (HHT1 and HHT2), respectively, a dominant vascular dysplasia caused by haploinsufficiency. No formal mutation studies of patients with HHT have been conducted in Spain. METHODS: ENG and ALK1 mutation analyses were carried out in 13 Spanish HHT patients diagnosed according to the Curacao criteria. Because endoglin is up-regulated at the cell surface during the monocyte-macrophage transition, endoglin concentrations in activated monocytes were determined by immunofluorescence flow cytometry in a systematic analysis. As controls, 40 non-HHT volunteers were studied for up-regulation of endoglin in activated monocytes. RESULTS: The mutation responsible for HHT was identified in eight patients belonging to two unrelated families. One of the families has a nonsense mutation in exon 4 (c.511C>T; R171X) of the ENG gene, and accordingly the disorder was identified as HHT1. The other family has a missense mutation affecting exon 8 (c.1120C>T; R374W) of the ALK1 gene, and hence is a HHT2 family. Interestingly, endoglin up-regulation was deficient in activated monocytes of both HHT1 and HHT2 patients compared with controls. By contrast, endoglin up-regulation was age-independent in control donors across a broad range of ages. The extent of endoglin up-regulation in activated monocytes was most diminished in those patients with the most severe symptoms. CONCLUSIONS: Endoglin up-regulation in activated monocytes is impaired in HHT1 and HHT2 patients and is age-dependent in both HHT types. Endoglin expression may predict the clinical severity of HHT.     

Migraines linked to intrapulmonary right-to-left shunt

OBJECTIVE: To determine if there is an association between migraines and intrapulmonary right-to-left shunt. BACKGROUND: Several studies have described an association between migraines and intracardiac right-to-left shunt. METHODS: Patients with hereditary hemorrhagic telangiectasia (HHT) were retrospectively recruited from the Toronto Hereditary Hemorrhagic Telangiectasia Center Clinical Database. All patients had been prospectively, systematically asked about a history of migraines and systematically screened for pulmonary and cerebral arteriovenous malformations (AVMs). All patients with a definite diagnosis of HHT, assessed during a 2-year period (February 1997 to April 1999), were included. Univariate analyses and logistic regression were performed, for migraine as the dependent variable and the following independent variables: age, sex, pulmonary AVMs, and cerebral AVMs. RESULTS: Of the 200 patients assessed during the 2-year period, 124 (62%) had a definite diagnosis of HHT and were included in the analysis. Eighty (65%) were females. Forty-seven (38%) of the HHT patients had a history of migraine, of whom 38 (81%) had migraine with aura. The prevalence of migraine was greater in patients with pulmonary AVMs (46%) compared to patients without pulmonary AVMs (33%), OR = 1.7 (0.8 to 3.6), though this did not reach statistical significance (P = .14). Pulmonary AVMs were significantly associated with migraine (OR = 2.4, 95% CI = 1.1 to 5.5, P = .04), after adjustment for age and sex, using logistic regression. CONCLUSIONS: There is a significant association between intrapulmonary right-to-left shunt and migraine.     

Matrix Gla protein deficiency causes arteriovenous malformations in mice

Arteriovenous malformations (AVMs) in organs, such as the lungs, intestine, and brain, are characteristic of hereditary hemorrhagic telangiectasia (HHT), a disease caused by mutations in activin-like kinase receptor 1 (ALK1), which is an essential receptor in angiogenesis, or endoglin. Matrix Gla protein (MGP) is an antagonist of BMPs that is highly expressed in lungs and kidneys and is regulated by ALK1. The objective of this study was to determine the role of MGP in the vasculature of the lungs and kidneys. We found that Mgp gene deletion in mice caused striking AVMs in lungs and kidneys, where overall small organ size contrasted with greatly increased vascularization. Mechanistically, MGP deficiency increased BMP activity in lungs. In cultured lung epithelial cells, BMP-4 induced VEGF expression through induction of ALK1, ALK2, and ALK5. The VEGF secretion induced by BMP-4 in Mgp^–/– epithelial cells stimulated proliferation of ECs. However, BMP-4 inhibited proliferation of lung epithelial cells, consistent with the increase in pulmonary vasculature at the expense of lung tissue in the Mgp-null mice. Similarly, BMP signaling and VEGF expression were increased in Mgp^–/– mouse kidneys. We therefore conclude that Mgp gene deletion is what we believe to be a previously unidentified cause of AVMs. Because lack of MGP also causes arterial calcification, our findings demonstrate that the same gene defect has drastically different effects on distinct vascular beds.     

Life expectancy in patients with hereditary haemorrhagic telangiectasia

BACKGROUND: There are few data on life expectancy in patients with hereditary haemorrhagic telangiectasia (HHT), a disorder with life-threatening complications. METHODS: Seventy HHT patients provided data on age and age at death of their HHT-affected parent, which was compared with that of the parent's non-affected partner. RESULTS: At the time of the study, 40 HHT parents (57.1%) vs. 36 (51.4%) non-HHT parents had died (p = 0.404). Median age at death was lower in HHT vs. non-HHT parents (63.2 vs. 70.0 years, respectively). The mortality of HHT parents showed an early peak in the under 50s and a late peak at 60-79 years. HHT was the main risk factor influencing life expectancy after 30 years (p < 0.05). No differences in survival probability were found in HHT patients with respect to sex (p = 0.37), or ENG vs. ALK-1 genotype (p < 0.9). DISCUSSION: Life expectancy appears to be significantly lower in HHT patients than in their partners. Prevention of HHT complications with screening programs could increase life expectancy.     

Quantification of right-to-left shunt with (99m)Tc-labelled albumin macroaggregates and 100% oxygen in patients with hereditary haemorrhagic telangiectasia

Pulmonary arteriovenous malformations (PAVMs) are often associated with hereditary haemorrhagic telangiectasia (HHT). The quantification of right-to-left shunts in patients with PAVMs is important in diagnosis and follow up. Traditionally, this shunt is measured by the 100% oxygen method, in which the value for the arteriovenous difference in oxygen content, Cao(2)-CVO(2) (where Cao(2) is the oxygen content of arterial blood and CVO(2) is the oxygen content of mixed venous blood) is estimated. Alternative methods consist of measurement of the systemic or renal uptake of (99m)Tc-labelled macroaggregates of albumin (MAA), which are trapped in pulmonary capillaries, but pass through PAVMs. We first measured Cao(2)-CVO(2) in 12 HHT patients before and after embolization of PAVMs. We obtained a mean value of 4.4 ml/100 ml, instead of the usual 5 ml/100 ml. Subsequently, we measured right-to-left shunt in 21 HHT patients using the 100% oxygen method and with two different methods involving (99m)Tc. We used the kidney-lung method (K/L method), in which it is assumed that the right kidney receives 10% of the cardiac output, and we also used a method with two tracers (HSA/MAA method): (1) (99m)Tc-labelled human serum albumin (HSA) (which passes through pulmonary capillaries) to measure the fraction of the cardiac output perfusing the kidneys, and (2) MAA to measure the shunt fraction. In 35 shunt measurements we evaluated this new technique and the K/L method, by comparing the results with those from the 100% oxygen method. There was poor agreement between the 100% oxygen method and the K/L method, with 95% limits of agreement for the shunt fraction of -15.2% to +15.2%. There was moderate agreement between the 100% oxygen method and the HSA/MAA method, with limits of agreement of -8.3% to +7.7%. We conclude that the different methods cannot replace each other, because the limits of agreement are too wide for clinical use.     

Altered endothelial gene expression associated with hereditary haemorrhagic telangiectasia

BACKGROUND: Mutations in endoglin (ENG) and activin receptor-like kinase 1 (ALK-1 or ACVRL1) genes are the underlying basis of hereditary haemorrhagic telangiectasia (HHT) types 1 and 2, respectively. Both genes belong to the transforming growth factor-beta (TGF-beta) receptors superfamily and are expressed in endothelial cells. The current model for HHT is that ENG or ALK-1 haplo-insufficiency affects angiogenesis and predisposes to vascular dysplasia and arteriovenous malformations. MATERIALS AND METHODS: Using microarray technology, we compared human umbilical vein endothelial cells (HUVEC) from newborns with ENG or ALK-1 mutations to control cells to search for gene profiles associated with early stages of the disease. Real-time polymerase chain reaction and Western blot analysis were used to validate a subset of the modulated genes and functionally related genes. RESULTS: Our results indicate that HHT endothelial cells in vitro display several gene expression disturbances, including genes associated with the activation phase of angiogenesis, with cell guidance and intercellular connections, and also with the TGF-beta pathway. Hierarchical clustering using modulated genes enables discrimination between affected and non-affected samples. CONCLUSION: HHT HUVECs display gene modulations which can suggest that ENG and ALK-1 haplo-insufficiency induces compensatory regulatory mechanisms at the expression levels.     

Hereditary hemorrhagic telangiectasia: children need screening too

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant blood vessel disorder characterized by the presence of arteriovenous malformations (AVMs), epistaxis, and mucocutaneous telangiectases. AVMs are present in lungs, brain, liver, and spine. Children and adults share the same manifestations, with epistaxis and skin telangiectases being the most common. Parents often seek medical attention for their children after an adult in the family is diagnosed. There is debate whether manifestations of HHT are present at birth or develop after puberty, thus making recommendations for evaluation or screening of children in families with HHT uncertain. In the authors' pediatric HHT center, potentially life-threatening manifestations of HHT have been identified in asymptomatic children under 12 years of age. Treatments for HHT include embolization and surgery, laser, and hormone therapy. It is imperative for nurses and other health professionals to recognize this disease and become familiar with evaluation and treatment options.     

Emergencies in hereditary haemorrhagic telangiectasia

BACKGROUND: Hereditary haemorrhagic telangiectasia (HHT) is a systemic autosomal dominant vascular disease. Although the clinical picture is that of a chronic disabling disease, vascular malformations can suddenly lead to life-threatening conditions. AIM: To assess the frequency and type of emergency acute complications in HHT. DESIGN: Retrospective case-note review. METHODS: From August 2000 to December 2004, our specialized HHT centre saw 139 patients (74 males, 65 females, mean age 45.5 years, range 14-77) with a definite diagnosis of HHT. We reviewed their clinical files and recorded all visits for acute complications (massive nosebleeds, haematemesis, melaena, haematochezia, haemothorax, haemoptysis, TIA/ischaemic stroke, haemorrhagic stroke, brain abscess). RESULTS: Fifty patients (35.9%) had at least one acute complication. There were a total of 93 visits potentially involving the emergency department. Most commonly, patients sought urgent medical attention for nosebleeds and gastrointestinal bleeding (63.4%), but there were also disorders of the brain, lung, heart and liver. DISCUSSION: Acute complications of HHT are not uncommon and can be severe and wide-ranging. Physicians should be aware of HHT and its major complications, as a prompt diagnosis is essential to direct patients to the most appropriate therapies, and to suggest screening for visceral involvement in their relatives.     

An association of migraine with hereditary haemorrhagic telangiectasia independently of pulmonary right-to-left shunts

Hereditary haemorrhagic telangiectasia (HHT) is a genetic disorder characterized by epistaxis, telangiectasia and visceral vascular manifestations. It is associated with migraine with aura due to pulmonary arteriovenous malformations (pAVMs). The aim of the study was to evaluate headache prevalence in 106 consecutive HHT patients (67 female, 39 male, age 53.5 ± 14.5 years) and age- and gender-matched controls. An extensive clinical work-up was performed and headache prevalence was determined. Lifetime prevalence of migraine was higher in HHT patients (39.6%) than in controls (19.8%) [ P  < 0.001, χ² = 12.17, odds ratio (OR) 3.0; 95% confidence interval 1.6 < OR < 5.7]. A positive association was confirmed between HHT patients with pAVMs and migraine with aura (38.5% vs. 10%). Furthermore, HHT patients without pAVMs had a higher prevalence of migraine without aura (11.5% vs. 26.3%; χ² = 11.85; d.f. = 2; P  = 0.003). We speculate that pathophysiological mechanisms, including dysfunction of the transforming growth factor-beta pathways and resulting vascular changes, contribute to the higher prevalence of migraine without aura in HHT patients without pAVMs.     

Ⅱ型遗传性出血性毛细血管扩张症血管生长发育相关蛋白质分析及意义

目的分析和检测1个Ⅱ型遗传性出血性毛细血管扩张症(HHT-2)家系成员血浆及外周血白细胞转化生长因子(TGF)-β1、TGF-β2、血管内皮生长因子(VFGF)、血小板源性生长因子受体α(PDGFRα)等蛋白质浓度,探讨这些血管生长发育相关蛋白在 HHT 发病机制中的变化及意义。方法根据鼻出血、毛细血管扩张及家族史进行 HHT 的临床诊断,并经基因筛查,以证实 HHT 的诊断。对该家系中5例新成员进行 HHT 的诊断和排除诊断。用 ELSA 方法检测该家系成员血浆 TGF-β1、TGF-β2及 VEGF 浓度;用流式细胞术结合直接按或间接免疫荧比技术分析该家系成员外周血白细胞TGF-β1、VEGF、及 PDGFRα蛋白表达。结果基因筛查的5例新家系成员 ALK1基因8号外显子不存在 C1231T 突变。该家系成员中3例 HHT 患者血浆 TGF-β1和 TGF-β2浓度分别为(16 954±3 709)ng/L和(11 548±2 611)ng/L;与正常对照相比差异无统计学意义(P>0.05);3例 HHT 患者、6名未受累家系成员、6名正常对照血浆 VEGF 浓度值分别为(179.2±22.0)μg/L,(149.8±22.7)μg/L,(132.9±21.0)μg/L;HHT 患告血浆 VEGF 浓度明显高于正常对照组(P<0.05)。HHT 家系成员外周血白细胞 PDGFRα和 VEGF 蛋白表达均上调(P 值均<0.05);TGF-β1蛋白表达与正常对照比较差异无统计学意义。结论 HHT-2患者血浆 TGF-β1浓度、单核细胞及粒细胞 TGF-β1蛋白表达与正常对照比较差异无统计学意义;而血浆 VEGF 浓度及外周血白细胞 VEGF 表达均明显高于正常对照;HHT-2患者外周血白细胞存在 PDGFRα高表达,提示存在血管生长发育相关蛋白的代偿机制。     

Reduced plasma levels of Ang-2 and sEng as novel biomarkers in hereditary hemorrhagic telangiectasia (HHT)

BackgroundHereditary hemorrhagic telangiectasia (HHT; OMIM 187300) is an autosomal dominant vascular disorder characterized by telangiectases and internal arteriovenous malformations caused by mutations in certain elements of the TGF-β receptor complex. In the case of HHT1 mutations in the endoglin gene are responsible, whereas mutations in the ALK1 gene (an activin receptor-like kinase 1), lead to HHT2. Another two loci found at chromosome 5 and chromosome 7, whose target genes remain unidentified, lead to types 3 and 4 of the disease, respectively. Mutations in the MADH4/SMAD4 gene, another member of the TGF-β signalling pathway, lead to a combined syndrome of familial juvenile polyposis associated with HHT.MethodsIn an attempt to identify some soluble components differentially expressed in the plasma of HHT patients, angiopoietin-2 and soluble endoglin concentrations were analyzed with standard quantitative sandwich ELISA.ResultsAngiopoietin-2 and soluble endoglin levels are reduced in plasma of HHT patients compared to control individuals, and a diagnostic algorithm for HHT based on these protein levels is proposed.ConclusionsDown-regulated protein levels of angiopoietin-2 and soluble endoglin in plasma represent novel HHT biomarkers that could be useful in the biochemical diagnosis of HHT facilitating the rapid identification of potential HHT patients.     

Evidence of small-bowel involvement in hereditary hemorrhagic telangiectasia: a capsule-endoscopic study

BACKGROUND AND STUDY AIMS: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal-dominant vascular disorder leading to telangiectases and arteriovenous malformations of the skin, mucosa, and viscera. Telangiectases in the upper gastrointestinal tract are known, but data regarding possible small-bowel involvement are scarce due to the technical difficulty of exploring the entire gastrointestinal tract. The aim of the present study was to use capsule endoscopy (CE) to determine the prevalence of small-bowel telangiectases in HHT patients. PATIENTS AND METHODS: From December 2001 to September 2002, 20 consecutive adult HHT patients at an interdepartmental HHT center were prospectively evaluated. All patients underwent esophagogastroduodenoscopy (EGD) followed by CE within 24 h. The telangiectases were scored according to commonly accepted criteria by two endoscopists and two observers of the video-capsule images, who were blinded to each other's findings. RESULTS: EGD revealed gastric telangiectases in 15 of the 20 patients (75 %), while CE demonstrated small-bowel involvement in 10 of 18 patients (56 %; images were not recorded for two patients due to battery failure). No preferential site for telangiectasia was found between the jejunum and the terminal ileum. All patients who were positive on CE were also found to have gastric involvement at EGD. Patients with small-bowel telangiectases were significantly older than those without (62.5 years vs. 45 years; P < 0.02). CONCLUSIONS: This study established a 56 % prevalence of small-bowel telangiectases in patients with HHT. This new endoscopic technique will probably change the etiological diagnosis of occult bleeding in HHT patients (which is too often attributed only to epistaxis) and may also be able to alter treatment strategies in HHT patients with gastrointestinal bleeding.     

Hereditary hemorrhagic telangiectasia: from molecular biology to patient care

Summary. Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder characterized by severe and recurrent nosebleeds, mucocutaneous telangiectases, and, in some cases, life‐threatening visceral arteriovenous malformations of various types, including pulmonary, hepatic, cerebral, and spinal. Gastrointestinal telangiectases are frequent and may cause severe bleeding. HHT type 1 results from mutations in ENG on chromosome 9 (coding for endoglin), and HHT type 2 results from mutations in ACVRL1 on chromosome 12 (coding for activin receptor‐like kinase 1). Mutations of either of these two genes account for most clinical cases. In addition, mutations in MADH4 (encoding SMAD4), which cause a juvenile polyposis/HHT overlap syndrome, have been described, and recently, an HHT3 locus on chromosome 5 (5q31.3–5q32) has been reported. The mutated genes in HHT encode proteins that modulate transforming growth factor‐β superfamily signaling in vascular endothelial cells. Management of patients has changed considerably in the last 20 years, in terms of both treatment and the prevention of complications. The goal of this review was to describe the underlying molecular and cellular physiopathology, explore clinical and genetic diagnostic strategies for HHT, and present clinical management recommendations in order to treat symptomatic disease and to screen for vascular malformations.     

High prevalence of hepatic focal nodular hyperplasia in subjects with hereditary hemorrhagic telangiectasia

A vascular pathogenesis of hepatic focal nodular hyperplasia (FNH) has been suggested; this study was aimed to evaluate in families with hereditary hemorrhagic telangiectasia (HHT) the prevalence of FNH, relating it to presence and stage of hepatic vascular malformations (VMs). Fifty-two HHT families underwent a screening program including abdominal Doppler sonography (US) searching for hepatic VMs; we classified them as minimal, moderate and severe, depending on the number and degree of abnormalities found by Doppler US. Presence of focal liver lesions was recorded. Diagnosis of FNH was made if at least two examinations, whether color Doppler US, liver scintigraphy, dynamic computed tomography (CT) or magnetic resonance (MR), showed suggestive findings. FNH was found in five out of 274 subjects (1.8%). All five were affected by HHT. Thus, percentage related to the group of affected patients increased to 2.9; 4/5 presented severe liver VMs. Female-to-male ratio was 4:1. FNH was single in three cases; tumor size ranged between 20 and 90 mm. During follow-up, no lesion showed a reduction in size, three showed an increase. Prevalence of FNH in patients with HHT is far greater than that reported in the general population; Doppler US role in its diagnosis and follow-up is highlighted.     

Hereditary haemorrhagic telangiectasia with atrial septal defect and pulmonary hypertension during advanced pregnancy: a case report and literature review

Pregnancy complicated with hereditary haemorrhagic telangiectasia (HHT) is a rare condition. This case report presents an extremely rare case with the co-occurrence of HHT and congenital heart disease. In this report, a 43-year-old woman at 36 + 4 weeks of gestation experienced haemoptysis with a volume of approximately 300 ml for the first time. Uncommonly, her transthoracic echocardiogram revealed a previously unrecognized atrial septal defect (ASD) and pulmonary hypertension (PH) for the first time at 36 + 1 weeks of gestation. Chest computed tomography revealed an arteriovenous malformation (AVM) in the right lower lobe of the lung. Due to concerns of rebleeding of ruptured pulmonary arteriovenous malformations (PAVMs), the patient underwent a caesarean section at 36 + 6 weeks of gestation. A healthy male infant weighing 2800 g was delivered. To the best of our knowledge, there have been few reports about HHT with ASDs and PH during advanced pregnancy. This current case report highlights the necessity for clinicians to pay considerable attention to cardiac structural abnormalities, which can worsen PAVM in patients with HHT during pregnancy, for whom terminating the pregnancy in time may reduce the risk of PAVM rupture.