Hereditary hemorrhagic telangiectasia: an overview of diagnosis, management, and pathogenesis. Genet Med. 2011;13:607-616. [PMID: 21546842 DOI: 10.1097/gim.0b013e3182136d32]

How I treat bleeding in hereditary hemorrhagic telangiectasia

ABSTRACT

Hereditary hemorrhagic telangiectasia (HHT; Osler-Weber-Rendu disease) affects 1 in 5000 persons, making it the second most common inherited bleeding disorder worldwide. Telangiectatic bleeding, primarily causing recurrent epistaxis and chronic gastrointestinal bleeding, is the most common and most important manifestation of this multisystem vascular disorder. HHT-associated bleeding results in substantial psychosocial morbidity and iron deficiency anemia that may be severe. Although there remain no regulatory agency-approved therapies for HHT, multiple large studies, including randomized controlled trials, have demonstrated the safety and efficacy of antifibrinolytics for mild-to-moderate bleeding manifestations and systemic antiangiogenic drugs including pomalidomide and bevacizumab for moderate-to-severe bleeding. This has led to a recent paradigm shift away from repetitive temporizing procedural management toward effective systemic medical therapeutics to treat bleeding in HHT. In this article, 4 patient cases are used to illustrate the most common and most challenging presentations of HHT-associated bleeding that hematologists are likely to encounter in daily practice. Built on a framework of published data and supported by extensive clinical experience, guidance is given for modern evidence-based approaches to antifibrinolytic therapy, antiangiogenic therapy, and iron deficiency anemia management across the HHT disease severity spectrum.

Tears of blood: an unusual case of haemolacria due to conjunctival vascular malformation successfully managed by embolisation

A boy in his mid-teens presented with progressively increasing bleeding from the right eye and nostril intermittently over a period of 6 weeks. A complete ophthalmic examination revealed nothing significant. His otorhinological examination and haematological investigations were within normal limits. The patient came a month later with frank bleeding from the right eye. Ophthalmic examination revealed hyperaemia and maceration of the right lower palpebral conjunctiva. A histopathological examination of conjunctival scrapings from the site showed abnormal dilated blood vessels suggestive of a vascular malformation. Digital subtraction angiography confirmed the presence of a conjunctival micro arteriovenous malformation supplied by the external carotid and ophthalmic artery branches. He underwent successful transarterial Onyx embolisation resulting in complete resolution of the haemolacria.

Arterial Spin-Labeling MR Imaging in the Detection of Intracranial Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia

BACKGROUND AND PURPOSE

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease that causes vascular malformations in a variety of organs and tissues, including brain AVMs. Because brain AVMs have the potential to cause disabling or fatal intracranial hemorrhage, detection of these lesions before rupture is the goal of screening MR imaging/MRA examinations in patients with HHT. Prior studies have demonstrated superior sensitivity for HHT-related brain AVMs by using postcontrast MR imaging sequences as compared with MRA alone. We now present data regarding the incremental benefit of including arterial spin-labeling (ASL) perfusion sequences as part of MR imaging/MRA screening in patients with this condition.

MATERIALS AND METHODS

We retrospectively analyzed 831 patients at the UCSF Hereditary Hemorrhagic Telangiectasia Center of Excellence. Of these, 42 patients had complete MR imaging/MRA, ASL perfusion scans, and criterion-standard DSA data. Two neuroradiologists reviewed imaging studies and a third provided adjudication when needed.

RESULTS

Eight patients had no brain AVMs detected on DSA. The remaining 34 patients had 57 brain AVMs on DSA. Of the 57 identified AVMs, 51 (89.5%) were detected on ASL and 43 (75.4%) were detected on conventional MR imaging/MRA sequences (P = .049), with 8 lesions detected on ASL perfusion but not on conventional MR imaging.

CONCLUSIONS

ASL provides increased sensitivity for brain AVMs in patients with HHT. Inclusion of ASL should be considered as part of comprehensive MR imaging/MRA screening protocols for institutions taking care of patients with HHT.

Identifying plasma proteomic signatures from health to heart failure, across the ejection fraction spectrum

Circulating proteins may provide insights into the varying biological mechanisms involved in heart failure (HF) with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF). We aimed to identify specific proteomic patterns for HF, by comparing proteomic profiles across the ejection fraction spectrum. We investigated 4210 circulating proteins in 739 patients with normal (Stage A/Healthy) or elevated (Stage B) filling pressures, HFpEF, or ischemic HFrEF (iHFrEF). We found 2122 differentially expressed proteins between iHFrEF-Stage A/Healthy, 1462 between iHFrEF-HFpEF and 52 between HFpEF-Stage A/Healthy. Of these 52 proteins, 50 were also found in iHFrEF vs. Stage A/Healthy, leaving SLITRK6 and NELL2 expressed in lower levels only in HFpEF. Moreover, 108 proteins, linked to regulation of cell fate commitment, differed only between iHFrEF-HFpEF. Proteomics across the HF spectrum reveals overlap in differentially expressed proteins compared to stage A/Healthy. Multiple proteins are unique for distinguishing iHFrEF from HFpEF, supporting the capacity of proteomics to discern between these conditions.

Cost-effectiveness of bevacizumab therapy in the care of patients with hereditary hemorrhagic telangiectasia

ABSTRACT

No US Food and Drug Administration- or European Medicines Agency-approved therapies exist for bleeding due to hereditary hemorrhagic telangiectasia (HHT), the second-most common inherited bleeding disorder worldwide. The current standard of care (SOC) includes iron and red cell supplementation, alongside the necessary hemostatic procedures, none of which target underlying disease pathogenesis. Recent evidence has demonstrated that bleeding pathophysiology is amenable to systemic antiangiogenic therapy with the anti-vascular endothelial growth factor bevacizumab. Despite its high cost, the addition of longitudinal bevacizumab to the current SOC may reduce overall health care resource use and improve patient quality of life. We conducted, to our knowledge, the first cost-effectiveness analysis of IV bevacizumab in patients with HHT with the moderate-to-severe phenotype, comparing bevacizumab added to SOC vs SOC alone. The primary outcome was the incremental net monetary benefit (iNMB) reported over a lifetime time horizon and across accepted willingness-to-pay thresholds, in US dollar per quality-adjusted life year (QALY). Bevacizumab therapy accrued 9.3 QALYs while generating $428 000 in costs, compared with 8.3 QALYs and $699 000 in costs accrued in the SOC strategy. The iNMB of bevacizumab therapy vs the SOC was $433 000. No parameter variation and no scenario analysis, including choice of iron supplementation product, changed the outcome of bevacizumab being a cost-saving strategy. Bevacizumab therapy also saved patients an average of 133 hours spent receiving HHT-specific care per year of life. In probabilistic sensitivity analysis, bevacizumab was favored in 100% of all 10 000 Monte Carlo iterations across base-case and all scenario analyses. Bevacizumab should be considered for more favorable formulary placement in the care of patients with moderate-to-severe HHT.

Prenatal diagnosis of pulmonary arteriovenous malformations with a postnatal diagnosis of Osler-Weber-Rendu syndrome

Hereditary Hemorrhagic Telangiectasia (HHT), commonly known as Osler-Weber-Rendu disease, is an autosomal dominant multisystemic vascular disease associated with approximately 70% of cases of pulmonary arteriovenous malformations (PAVMs). Prenatal cases of PAVMs typically present with pulmonary vein dilatation on ultrasonography. This study presents a prenatal diagnosis of PAVMs with enlarged right pulmonary vein, cardiomegaly, cystic-appearing areas in the right lung and subsequent confirmation of Osler-Weber-Rendu syndrome using autopsy and whole exom sequencing.

Pulmonary arteriovenous malformations in Rendu-Osler-Weber syndrome

Rendu-Osler-Weber syndrome, also known as hereditary hemorrhagic telangiectasia, is an autosomal dominant hereditary disorder. It is characterized by presence of multiple arteriovenous malformations (AVMs) and telangiectasias. This article reports two cases of patients with Rendu-Osler-Weber syndrome who had pulmonary AVMs and underwent successful endovascular treatment. A brief review of the literature shows that up to 50% of patients with the syndrome have pulmonary AVMs and there is usually a positive family history in these patients. These pulmonary AVMs are multiple in 30% of cases and are associated with the most severe disease complications. Most patients are asymptomatic, even in the presence of AVMs with right-left shunts. When these shunts exceed 25% of the total blood volume, dyspnea, cyanosis, digital clubbing, and extracardiac murmurs may occur. Endovascular treatment is safe and offers control of complications from hereditary hemorrhagic telangiectasia and is currently the treatment of choice for these lesions.

Elevated FVIII levels in hereditary hemorrhagic telangiectasia: Implications for clinical management

Objectives

The objective of this study was twofold: to determine the prevalence of arterial and venous thromboembolic events in the Norwegian Hereditary Hemorrhagic Telangiectasia (HHT) population, and to explore potential factors linked to such events, with particular emphasis on FVIII.

Methods

Patients with an HHT diagnosis attending the Otorhinolaryngology Department at Oslo University Hospital-Rikshospitalet were included consecutively between April 2021 and November 2022. We recorded the participants' medical history with an emphasis on thromboembolic events. Measurements of blood constituents, including FVIII, FIX, vWF, hemoglobin, iron, ferritin, and CRP were performed.

Results

One hundred and thirty-four patients were included in the study. The total prevalence of thromboembolic events among the participants was 23.1%. FVIII levels were high (>150 IU/dL) in the majority of HHT patients (n = 84) (68.3%) and were significantly associated with thromboembolic events (p < .001), as was age. Of the patients with high FVIII levels, 28 (33%) had experienced a thromboembolic event. Furthermore, FVIII levels were measured consecutively in 51 patients and were found to fluctuate above or below 150 IU/dL in 25% of these cases.

Conclusion

Thromboembolic events are highly prevalent in the Norwegian HHT population and are significantly associated with FVIII levels. FVIII levels can fluctuate, and measurements should be repeated in HHT patients to assess the risk of thromboembolic events.

Level of Evidence

4.

NRP1 interacts with endoglin and VEGFR2 to modulate VEGF signaling and endothelial cell sprouting

Endothelial cells express neuropilin 1 (NRP1), endoglin (ENG) and vascular endothelial growth factor receptor 2 (VEGFR2), which regulate VEGF-A-mediated vascular development and angiogenesis. However, the link between complex formation among these receptors with VEGF-A-induced signaling and biology is yet unclear. Here, we quantify surface receptor interactions by IgG-mediated immobilization of one receptor, and fluorescence recovery after photobleaching (FRAP) measurements of the mobility of another coexpressed receptor. We observe stable ENG/NRP1, ENG/VEGFR2, and NRP1/VEGFR2 complexes, which are enhanced by VEGF-A. ENG augments NRP1/VEGFR2 interactions, suggesting formation of tripartite complexes bridged by ENG. Effects on signaling are measured in murine embryonic endothelial cells expressing (MEEC+/+) or lacking (MEEC-/-) ENG, along with NRP1 and/or ENG overexpression or knockdown. We find that optimal VEGF-A-mediated phosphorylation of VEGFR2 and Erk1/2 requires ENG and NRP1. ENG or NRP1 increase VEGF-A-induced sprouting, becoming optimal in cells expressing all three receptors, and both processes are inhibited by a MEK1/2 inhibitor. We propose a model where the maximal potency of VEGF-A involves a tripartite complex where ENG bridges VEGFR2 and NRP1, providing an attractive therapeutic target for modulation of VEGF-A signaling and biological responses.

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

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.

Health-Related Quality of Life Outcome Measures in Individuals With Hereditary Hemorrhagic Telangiectasia: A Scoping Review

BACKGROUND

Studies evaluating health-related quality of life (HRQOL) in patients with hereditary hemorrhagic telangiectasia (HHT) have expanded rapidly in the past decade. These studies have evaluated QOL aspects ranging from the general QOL for patients living with HHT to intervention-specific outcomes. However, few tools have been fully validated across the spectrum of disease manifestations and interventions in HHT.

OBJECTIVE

In this scoping review, we aim to map the literature on HHT-QOL metrics, identify gaps, inform future QOL research, and facilitate future metric development.

METHODS

We analyzed articles in English that assessed at least 1 measure of general HRQOL, including physical health, mental health, social health, or intervention-specific QOL in patients with HHT. Searches across 2 bibliographic databases (PubMed and Scopus) yielded 186 articles after duplicates were removed. Sixty-three studies met eligibility criteria: 22 prospective studies (34.9%), 20 retrospective studies (31.7%), 12 cross-sectional studies (17.5%), 6 randomized controlled trials or secondary analyses of a randomized controlled trials (9.5%), 2 qualitative studies (3.2%), and 1 case-control study (1.6%). Two additional studies-1 prospective and 1 cross-sectional study-were identified at the October 2022 14th International HHT Conference and included, making a total of 65 studies.

RESULTS

The 65 eligible studies used 30 QOL instruments. Twenty studies characterized baseline HRQOL, and 45 studies evaluated QOL before and after treatment. Of those 45 studies, 37 evaluated HRQOL before and after therapies targeting epistaxis and nasal symptoms, 4 targeted therapies for liver arteriovenous malformations and high-output heart failure, 3 evaluated therapies for both epistaxis and gastrointestinal bleeding, and 1 evaluated treatment targeting gastrointestinal bleeding alone.

CONCLUSIONS

Comparison of results across studies remains challenging given the heterogeneity in outcomes measures. Further development of HHT-specific patient-reported outcomes instruments that capture the global illness experience of HHT is needed.

Prevalence and Characteristics of Intracranial Aneurysms in Hereditary Hemorrhagic Telangiectasia

BACKGROUND AND PURPOSE

The association between hereditary hemorrhagic telangiectasia and intracranial aneurysms remains controversial. This study evaluated the prevalence and characteristics of intracranial aneurysms in patients with hereditary hemorrhagic telangiectasia with brain vascular malformations.

MATERIALS AND METHODS

Between 2007 and 2021, patients enrolled in the Brain Vascular Malformation Consortium with definite hereditary hemorrhagic telangiectasia, the presence of brain vascular malformations, and available angiographic studies of the brain were retrospectively reviewed. Angiographic features of intracranial aneurysms and their relationship to coexisting brain vascular malformations were analyzed. We also examined the association between baseline clinical features and the presence of intracranial aneurysms.

RESULTS

One hundred eighty patients were included. A total of 14 intracranial aneurysms were found in 9 (5%) patients, and 4 intracranial aneurysms were considered flow-related aneurysms. Patients with intracranial aneurysms were significantly older than patients without intracranial aneurysms (mean, 48.1 [SD, 18.2] years versus 33.5 [SD, 21.0] years; P = .042). If we excluded flow-related intracranial aneurysms, the prevalence of intracranial aneurysms was 3.3%. All intracranial aneurysms were in the anterior circulation, were unruptured, and had an average maximal diameter of 3.9 (SD, 1.5) mm. No intracranial aneurysms were found in pediatric patients with hereditary hemorrhagic telangiectasia. No statistically significant correlation was observed among other baseline demographics, hereditary hemorrhagic telangiectasia features, and the presence of intracranial aneurysms.

CONCLUSIONS

The prevalence of intracranial aneurysms in this large cohort study is comparable with that in the general population and might be increased slightly due to hemodynamic factors associated with shunting brain vascular malformations.

Oral manifestations and dental considerations of patients with hereditary hemorrhagic telangiectasia: a scoping review

OBJECTIVE

We examined the range, nature, and extent of research conducted regarding the oral and dental implications of hereditary hemorrhagic telangiectasia (HHT) to identify gaps in the research and knowledge of the field.

STUDY DESIGN

We performed a scoping review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews and 2017 Guidance for the Conduct of Joanna Briggs Institute Scoping Reviews. We searched the MEDLINE and Web of Science databases for all full-text articles published in English from December 1946 to October 2022.

RESULTS

We identified 103 articles describing oral and dental considerations of patients with HHT, primarily case reports. Most reported oral telangiectasias of the tongue, lips, and palate. Many reported management of bleeding and the use or recommendation of prophylactic antibiotics before dental procedures.

CONCLUSIONS

Oral telangiectasias are commonly found in patients with hereditary hemorrhagic telangiectasia, and dental professionals may be the first to diagnose it in their patients. Early detection and diagnosis are important to prevent potentially fatal outcomes, and prophylactic antibiotics before procedures may be warranted.

Exploring effects of atmospheric conditions in hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disorder characterized by recurrent epistaxis, telangiectasias, and visceral arteriovenous malformations. Individuals with HHT often identify low humidity and temperature as detrimental to epistaxis severity. We set out to assess the relationship between humidity and temperature on epistaxis severity in patients with HHT.

METHODS

Retrospective cross-sectional study at an academic hospital with an HHT center between July 1, 2014 and January 1, 2022. The primary outcome of this study was ESS. Pearson correlation analyses and multiple linear regression analyses were performed to test the association between weather variables and epistaxis severity scre (ESS). Results were reported as coefficient and 95% confidence interval (CI).

RESULTS

Four hundred twenty-nine patients were included in the analysis. Through a Pearson correlation analysis, neither humidity (regression coefficient = -0.01; 95% CI, -0.006 to 0.003; p = 0.50), daily low temperature (regression coefficient = 0.01; 95% CI, -0.011 to 0.016; p = 0.72), or daily high temperature (regression coefficient = 0.01; 95% CI, -0.004 to 0.013; p = 0.32) were significantly correlated with ESS. In a multiple linear regression analysis, adjusting for both daily low temperature and humidity, medications taken, demographics, and genotype, neither daily low temperature (regression coefficient = -0.02; 95% CI, -0.04 to 0.01; p = 0.14) nor humidity (regression coefficient = 0.01; 95% CI, -0.01 to 0.01; p = 0.64) were significantly associated with ESS.

CONCLUSION

We have shown in a large clinical sample that neither humidity nor temperature were strongly correlated with HHT patient epistaxis severity.

Glucuronidation Pathways of 5- and 7-Hydroxypropranolol: Determination of Glucuronide Structures and Enzyme Selectivity

Propranolol, a non-selective beta-blocker medication, has been utilized in the treatment of cardiovascular diseases for several decades. Its hydroxynaphthyl metabolites have been recognized to possess varying degrees of beta-blocker activity due to the unaltered side-chain. This study achieved the successful separation and identification of diastereomeric glucuronic metabolites derived from 4-, 5-, and 7-hydroxypropranolol (4-OHP, 5-OHP, and 7-OHP) in human urine. Subsequently, reaction phenotyping of 5- and 7-hydroxypropranolol by different uridine 5'-diphospho-glucuronosyltransferases (UGTs) was carried out, with a comparison to the glucuronidation of 4-hydroxypropranolol (4-OHP). Among the 19 UGT enzymes examined, UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2A1, and UGT2A2 were found to be involved in the glucuronidation of 5-OHP. Furthermore, UGT1A6 exhibited glucuronidation activity towards 7-OHP, along with the aforementioned eight UGTs. Results obtained by glucuronidation of corresponding methoxypropranolols and MS/MS analysis of 1,2-dimethylimidazole-4-sulfonyl (DMIS) derivatives of hydroxypropranolol glucuronides suggest that both the aromatic and aliphatic hydroxy groups of the hydroxypropranolols may be glucuronidated in vitro. However, the analysis of human urine samples collected after the administration of propranolol leads us to conclude that aromatic-linked glucuronidation is the preferred pathway under physiological conditions.

Percutaneous embolization of pulmonary arteriovenous malformations in adult patient with Rendu-Osler-Weber: a case report

Background

Hereditary haemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber syndrome, is a rare genetic disorder characterized by the development of telangiectasias and arteriovenous malformations (AVMs) throughout the body. We present a case of percutaneous embolization of pulmonary AVMs in an adult patient.

Case summary

A 26-year-old male patient with polycythaemia of unknown origin and a family history of secundum atrial septal defect underwent cardiac evaluation which revealed clubbing as a sign of peripheral cyanosis. Transthoracic echocardiography showed no intracardiac shunting, but further imaging revealed pulmonary AVMs in the lower lobe of the left lung. Magnetic resonance imaging of the brain detected vascular-ischaemic lesions, likely due to embolization through the pulmonary malformations. Right heart catheterization and pulmonary angiography confirmed the presence of large AVMs in the left lower pulmonary lobe. Percutaneous closure using Amplatzer devices was performed, followed by temporary anticoagulation therapy. Oxygen saturation improved and follow-up imaging confirmed successful closure of the AVMs. Genetic testing using whole exome sequencing identified a mutation in the ENG gene, confirming the diagnosis of HHT.

Discussion

Our case highlights the importance of investigating both intra- and extracardiac shunting in patients with clinical features of right-to-left shunting. Arteriovenous malformations can serve as a pathway for paradoxical emboli, potentially leading to ischaemic brain events, and might cause pulmonary arterial hypertension. Screening for arteriovenous malformations in various organs and embolization of significant shunts are essential aspects of managing HHT. Genetic testing aids in confirming the diagnosis and guides family testing.

Identifying racial disparities in hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disorder characterized by recurrent epistaxis (nose bleeds), mucosal telangiectasias (spider veins), and arteriovenous malformations. Although HHT affects all racial groups, few studies have explored racial disparities among patients with HHT.

METHODS

We performed a retrospective chart review of HHT patients who were seen at a single academic center between July 1, 2014 and January 1, 2022. The primary outcomes of this study were the Epistaxis Severity Score (ESS) and the presence of pulmonary, cerebral, gastrointestinal, spinal, and hepatic arteriovenous malformations (AVMs). We analyzed racial differences using t-tests and analysis of variance (ANOVA) for continuous variables, and chi-squared tests for categorical variables. We then performed multivariable linear and logistic regressions on outcomes.

RESULTS

Our review identified 35 Asian, 6 Black or African American, 72 Hispanic or Latino, and 244 White or Caucasian patients who met the inclusion criteria. Through an analysis of variance model, race/ethnicity was not significantly associated with ESS. Two univariable logistic regression models between race and both pulmonary and brain AVMs showed that race was associated with the incidence of pulmonary AVMs (p<0.01), with Asian patients at a 2.3-fold increased risk of pulmonary AVMs compared with White patients (p=0.03). Race was also associated with the incidence of cerebral AVMs (p<0.01) with Hispanic or Latino patients at a 4.8-fold increased risk compared with White patients (p<0.01).

CONCLUSION

Patients who identified as Asian may have higher rates of pulmonary AVMs while patients identifying as Hispanic or Latino may have more cerebral AVMs. The correlations may be important for identifying risk factors in certain patient populations.

Multifocal Abscesses, Necrotizing Fasciitis, Iron Deficiency Anemia, and Hypophosphatemia Induced by Ferric Carboxymaltose Infusions: Report of a Case of Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant vascular dysplasia in which disrupted angiogenesis leads to increased formation of mucocutaneous telangiectasias or major vascular malformations. Iron deficiency anemia and recurrent abscesses are commonly reported in these patients, reinforcing screening and targeted therapies for these conditions. We report a 50-year-old man with HHT affected by repeated episodes of iron deficiency anemia secondary to recurrent epistaxis requiring frequent intravenous iron infusions. He eventually developed hypophosphatemia and hyperphosphaturia secondary to ferric carboxymaltose. He also had a history of recurrent multifocal abscesses, including a severe presentation of necrotizing fasciitis, requiring multiple surgical interventions. Despite the identification of hypogammaglobulinemia, only after consistent dental treatment and antibiotic prophylaxis did the abscesses stop recurring. We highlight the need for careful consideration of all possible complications inherent to the disease itself but also those related to comorbidities or existing treatments.

Hereditary Hemorrhagic Telangiectasia in a Young Adult: Gastrointestinal Arteriovenous Malformations as a Presenting Feature

Hereditary hemorrhagic telangiectasia (HHT) is characterized by the presence of multiple arteriovenous malformations (AVM) in which arteries and venules are connected directly without intervening capillaries. The primary clinical presentation is spontaneous and recurrent nosebleeds (epistaxis), typically starting around 12. Telangiectases, which are small arteriovenous malformations, are commonly found in mucocutaneous areas and gastrointestinal (GI) mucosa. The presentation of epistaxis precedes the occurrence of telangiectases. Larger AVMs most commonly affect the lungs, liver, or brain, and complications from bleeding or shunting can be potentially life-threatening. Here, we discuss the case of a 44-year-old man who presented to the emergency department with a chief complaint of fatigue for three weeks associated with shortness of breath. His eventual labs revealed severe anemia with a hemoglobin of 4.4 g/dL. He denied any history of symptoms of GI bleeding. Computed tomography of the abdomen was done which did not reveal any intra-abdominal bleeding, hematoma, or abnormality. Further history revealed a recent diagnosis of HHT in his mother through genetic testing. During the stay, he also developed spontaneous epistaxis which was treated with topical vasoconstrictors by the ear, nose, and throat (ENT) physician. Given the high likelihood of HHT, he underwent luminal evaluation. Upper and lower endoscopies of the gut revealed multiple AVMs. A diagnosis of HHT was established as he fulfilled the criteria required for the diagnosis of HHT. It is rare for individuals with HHT to experience GI bleeding before the age of 50, making this case unique.

Impact of SARS-CoV-2 infection in patients with hereditary hemorrhagic telangiectasia: epidemiological and clinical data from the comprehensive Italian retrospective multicenter study

Rare Disease patients manifested high concern regarding the possible increased risk of severe outcomes and worsening of disease-specific clinical manifestation due to the impact of COVID-19. Our aim was to assess the prevalence, outcomes, and impact of COVID-19 in patients with a rare disease such as Hereditary Hemorrhagic Telangiectasia (HHT) in Italian population. A nationwide, multicentric, cross-sectional observational study was conducted on patients with HHT from five Italian HHT centers by online survey. The association between COVID-19-related signs and symptoms and nosebleeds worsening, the impact of personal protective equipment on nosebleeds pattern, and the relationship between the presence of visceral AVMs and severe outcomes were analyzed. Out of 605 total survey responses and eligible for analysis, 107 cases of COVID-19 were reported. A mild-course COVID-19 disease, not requiring hospitalization, was observed in 90.7% of patients, while the remaining eight cases needed hospitalization, two of them requiring intensive-care access. No fatal outcome was recorded and 79.3% of patients reported a complete recovery. No difference in infection risk and outcome between HHT patients and general population was evidenced. No significative interference of COVID-19 on HHT-related bleeding was found. The majority of patients received COVID-19 vaccination, with relevant impact on symptoms and need for hospitalization in case of infection. COVID-19 in HHT patients had an infection profile similar to the general population. COVID-19 course and outcome were independent from any specific HHT-related clinical features. Moreover, COVID-19 and anti-SARS-CoV-2 measures did not seem to affect significantly HHT-related bleeding profile.

The Shunt of It

Pulmonary arteriovenous malformations (PAVMs) are rare and most often identified in patients with hereditary hemorrhagic telangiectasia (HHT). We describe a patient with severe hypoxemia and orthodeoxia with imaging findings consistent with PAVMs. Resected lung pathologic findings confirmed the presence of numerous microscopic vascular abnormalities within the right lower lobe that was consistent with diffuse pulmonary arteriovenous shunts. Family history was negative for HHT but was positive for pulmonary arterial hypertension (PAH) in two second-degree relatives. A vascular malformation gene panel was negative for genes that commonly are associated with HHT but identified a pathogenic variant in the gene encoding bone morphogenetic protein receptor-2 (BMPR2 p.Cys123∗). Pathogenic variants in BMPR2 are a well-known cause of hereditary PAH; there have been several reports to date of patients with PAVMs and PAH. However, this is the first patient to be reported with a pathogenic variant in BMPR2 to have PAVMs in isolation.

Silicone septal splint for recurrent epistaxis in HHT patients: experience of a national referral centre

Objective

To report our experience in the use of silicone septal splint for recurrent severe epistaxis in hereditary haemorrhagic telangiectasia patients (HHT).

Methods

This is a descriptive analysis carried out at the Otorhinolaryngology Department of Fondazione IRCCS Policlinico San Matteo in Pavia, a reference centre for the treatment and diagnosis of HHT. We retrospectively evaluated HHT patients who underwent silicone septal splint positioning after the endoscopic surgical treatment of epistaxis from 2000 to 2022.

Results

Of the 506 patients surgically treated in the period of analysis, 74 patients underwent silicone septal splint positioning and 37 were post-operatively interviewed. With a mean of 2.4 previous surgical treatments and a mean epistaxis severity of 7.38, the majority of patients presented with septal perforation (71.6%). On average, patients maintained the splint in place for 54.5 months, with a good tolerability and a significant reduction in epistaxis severity, need for blood transfusion and improvement of haemoglobin levels.

Conclusions

In HHT patients with recurrent severe epistaxis and with septal perforation, the placement of septal splints offers a useful additional strategy in the management of nosebleeds.

Improving Hereditary Hemorrhagic Telangiectasia Molecular Diagnosis: A Referral Center Experience

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare vascular disease inherited in an autosomal dominant manner. Disease-causing variants in endoglin (ENG) and activin A receptor type II-like 1 (ACVRL1) genes are detected in more than 90% of the patients undergoing molecular testing. The identification of variants of unknown significance is often seen as a challenge in clinical practice that makes family screening and genetic counseling difficult. Here, we show that the implementation of cDNA analysis to assess the effect of splice site variants on mRNA splicing is a powerful tool.

METHODS

Gene panel sequencing of genes associated with HHT and other arteriovenous malformation-related syndromes was performed. To evaluate the effect of the splice site variants, cDNA analysis of ENG and ACVRL1 genes was carried out.

RESULTS

three novel splice site variants were identified in ENG (c.68-2A > T and c.1311+4_1311+8del) and ACVLR1 (c.526-6C > G) genes correspondingly in three individuals with HHT that met ≥ 3 Curaçao criteria. All three variants led to an aberrant splicing inducing exon skipping (ENG:c.68-2A > T and ACVRL1:c.526-6C > G) or intron retention (ENG:c.1311+4_1311+8del) allowing the confirmation of the predicted effect on splicing and the reclassification from unknown significance to pathogenic/likely pathogenic of two of them.

CONCLUSIONS

RNA analysis should be performed to assess and/or confirm the impact of variants on splicing. The molecular diagnosis of HHT patients is crucial to allow family screening and accurate genetic counseling. A multidisciplinary approach including clinicians and geneticists is crucial when dealing with patients with rare diseases.

Genetics of brain arteriovenous malformations and cerebral cavernous malformations

Cerebrovascular malformations comprise abnormal development of cerebral vasculature. They can result in hemorrhagic stroke due to rupture of lesions as well as seizures and neurological defects. The most common forms of cerebrovascular malformations are brain arteriovenous malformations (bAVMs) and cerebral cavernous malformations (CCMs). They occur in both sporadic and inherited forms. Rapidly evolving molecular genetic methodologies have helped to identify causative or associated genes involved in genesis of bAVMs and CCMs. In this review, we highlight the current knowledge regarding the genetic basis of these malformations.

Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: research priorities for mucocutaneous bleeding disorders

BACKGROUND

Excessive or abnormal mucocutaneous bleeding (MCB) may impact all aspects of the physical and psychosocial wellbeing of those who live with it (PWMCB). The evidence base for the optimal diagnosis and management of disorders such as inherited platelet disorders, hereditary hemorrhagic telangiectasia (HHT), hypermobility spectrum disorders (HSD), Ehlers-Danlos syndromes (EDS), and von Willebrand disease (VWD) remains thin with enormous potential for targeted research.

RESEARCH DESIGN AND METHODS

National Hemophilia Foundation and American Thrombosis and Hemostasis Network initiated the development of a National Research Blueprint for Inherited Bleeding Disorders with extensive all-stakeholder consultations to identify the priorities of people with inherited bleeding disorders and those who care for them. They recruited multidisciplinary expert working groups (WG) to distill community-identified priorities into concrete research questions and score their feasibility, impact, and risk.

RESULTS

WG2 detailed 38 high priority research questions concerning the biology of MCB, VWD, inherited qualitative platelet function defects, HDS/EDS, HHT, bleeding disorder of unknown cause, novel therapeutics, and aging.

CONCLUSIONS

Improving our understanding of the basic biology of MCB, large cohort longitudinal natural history studies, collaboration, and creative approaches to novel therapeutics will be important in maximizing the benefit of future research for the entire MCB community.

A GDF2 missense mutation potentially involved in the pathogenesis of hereditary hemorrhagic telangiectasia: a case report

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disease. ENG and ACVRL1 gene variants account for up to 96% of all cases, while the remaining cases are caused by SMAD4 or GDF2 variants, or by currently undiscovered mutations in coding or non-coding regions. Here, we report a 47-year-old man who presented with duodenal bulb bleeding and chronic anemia. Physical examination also revealed bleeding from the skin and gingiva. His parents were cousins and one brother and one sister died in infancy from anemia and bleeding. Head computed tomography angiography (CTA) revealed a complete fetal posterior cerebral artery located in the left side, and pulmonary CTA showed pulmonary arterial hypertension. The patient was diagnosed with HHT. Peripheral blood was collected for whole-exome sequencing. Sequencing revealed a mutation in the GDF2 gene, which encodes bone morphogenetic protein-9 (BMP-9). The detected variant, c.352A > T(p.Ile118Phe), was predicted to be a neutral polymorphism; however, the patient's plasma BMP-9 levels were greatly reduced; we predicted that this might be caused by the GDF2 variant and might be involved in the HHT pathogenesis. Further research in cell lines and animal models is needed to verify the correlation between this GDF2 variant and the pathogenesis of HHT.

Brain Abscess as a Complication of Hereditary Hemorrhagic Telangiectasia: A Case Report

An 18-year-old male, previously diagnosed with hereditary hemorrhagic telangiectasia (HHT), presented to the outpatient department with a complaint of generalized seizures and fever for the past five days. He had a history of recurrent epistaxis, progressive shortness of breath, and cyanosis. Magnetic resonance imaging (MRI) of the brain revealed an abscess in the temporoparietal region. A computed angiogram of the pulmonary vasculature showed the presence of arteriovenous malformation (AVM). A four-weekly antibiotic regimen was initiated, which resulted in a profound improvement in symptoms. A brain abscess can arise as a complication of vascular malformation in a patient with HHT, providing a nidus for bacteria to migrate toward the brain. Early recognition of HHT is essential in these patients and their affected family members, as screening can help us prevent complications at an earlier stage.

Pulmonary Arteriovenous Malformation in a Rare Case of Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia is a rare condition presenting with anemia requiring transfusion and nosebleeds often refractory to supportive therapy. We discuss a case of a male in his 60s with a history of epistaxis, anemia requiring transfusions, and acute on chronic worsening shortness of breath presenting for evaluation. He was diagnosed with hereditary hemorrhagic telangiectasia. In addition, he was found to have pulmonary arteriovenous malformations and nonbleeding gastric telangiectasias. The patient underwent coil embolization of pulmonary arteriovenous malformations with a resolution of his shortness of breath and his anemia improved with iron supplementation.

Case report: Diagnosis of hereditary hemorrhagic telangiectasia (Osler Weber Rendu Syndrome) in a 23-year-old male presented with anemia and thrombocytopenia and its response to bevacizumab

Osler Weber Rendu Syndrome (OWS) is characterized by the development of abnormally dilated blood vessels, which manifest as arteriovenous shunts (pulmonary, gastrointestinal, hepatic, and cerebral) and mucocutaneous telangiectasias (lips, tongue, and fingertips). It is an autosomal dominant disease with a defect in transforming growth factor beta superfamily genes. This defect results in increased angiogenesis and disruption of vessel wall integrity. The disease remains underreported, with occasional history of recurrent epistaxis, iron deficiency anemia, and gastrointestinal bleeding in moderate to severe cases. Diagnosis is based on clinical presentation and confirmed by genetic testing. Various local (nasal saline, air humidification, laser ablation, and electric cauterization for epistaxis and endoscopic Argon Plasma Coagulation-APC for active GI bleeding), surgical, and systemic (tranexamic acid and antiangiogenic agents like bevacizumab and thalidomide) treatment options are used depending upon disease severity. Here, we present a case with recurrent gastrointestinal bleeding refractory to endoscopic APC ablation and thalidomide and severe symptomatic anemia requiring multiple packed red cell transfusions. The patient was ultimately started on bevacizumab, to which he had a good response and has remained in remission for 8 months as of now. This case emphasizes the need to have a low threshold of suspicion to diagnose HHT and start targeted therapy like bevacizumab early on in moderate to severe cases of HHT rather than just relying on temporizing palliative measures like ablation, cauterization, and tranexamic acid.

Rendú Osler Weber Syndrome; case report

Hereditary hemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber disease, is a dominant autosomal disease characterized by the presence of multiple telangiectasia in skin and mucus, associated with arteriovenous malformations (AVM) of various organs, including the lungs, gastrointestinal system and brain. HHT is presented most frequently as recurrent, spontaneous epistaxis. Patients may also present digestive, pulmonary and intracranial hemorrhage, as well as secondary anemia.

This article reports the case of a female patient, 62 years old, with multiple episodes of epistaxis and vaginal bleeding, with diagnosis of complex HHT, which was managed with multiple embolizations, which improved symptoms and survival. In this kind of patient, it is possible, with timely diagnosis and treatment, to obtain a greater quality and expectation of life. Due to the fact that the severity and alterations in each patient are so variable, management should be individualized.

Bronchoscopy-guided removal of intrabronchial coil migration after coil embolization of pulmonary arteriovenous malformation

Pulmonary arteriovenous malformations develop in approximately 50% of hereditary hemorrhagic telangiectasia patients. Pulmonary arteriovenous malformations are often treated with coil embolization therapy. We report a case of a 45-year-old female with multiple pulmonary arteriovenous malformations due to underlying hereditary hemorrhagic telangiectasia who had undergone 14 coil embolization procedures over 16 years. She presented with sudden onset severe, unremitting, nonproductive cough from a foreign body sensation in the airway. Computed tomography of the chest demonstrated a metallic foreign body extending from the left lower lobe of the lung into the left mainstem bronchus and trachea. Bronchoscopy-guided removal of the foreign body revealed an intact embolization coil placed 8 years prior to presentation had partially migrated through the vessel and airway walls into the airway lumen, extending from the left lower lobe bronchus to the left mainstem bronchus. Coil migration is a rare, but potentially dangerous, complication of coil embolization therapy.

Development and performance of a hereditary hemorrhagic telangiectasia-specific quality-of-life instrument

Hereditary hemorrhagic telangiectasia (HHT) is characterized by arteriovenous malformations and telangiectasia, with primary clinical manifestations of epistaxis and gastrointestinal bleeding and resultant anemia. HHT negatively affects health-related quality of life (HR-QoL); however, existing tools to measure HR-QoL are not HHT specific. Our objective was to develop an HHT-specific HR-QoL (HHT-QoL) instrument and evaluate its performance in a cross-sectional survey of individuals with HHT. Four HHT-specific questions were developed to evaluate the impact of HHT on productivity and social and personal interactions. An anonymous e-mail survey was conducted through Cure HHT. Participants also indicated their perceived HHT severity and completed 3 Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaires: Discretionary Social Activities, Social Roles, and Emotional Distress. Complete data were available for 290 participants who self-identified their HHT severity as mild (29%), moderate (46%), or severe (25%). The HHT-QoL scale was reliable (Cronbach's-α, 0.83). Principal components analysis indicated the instrument was unidimensional. Participants had low levels of QoL with their ability to participate in discretionary social activities (PROMIS mean 36.4 [standard deviation 14.3]) and perform in social roles (41.5 [17.2]), and the presence of a high level of emotional distress (64.8 [24.2]). The HHT-QoL score correlated negatively with PROMIS Discretionary Social Activities (r = -0.65) and Social Roles (r = -0.68) and positively correlated with PROMIS Emotional Distress (r = 0.51). In conclusion, the 4-item HHT-QoL instrument provides valuable insight and may be a useful addition to future clinical research in HHT.

A case of hereditary hemorrhagic telangiectasia and literature review

Background

To discuss the clinical features of a patient with hereditary hemorrhagic telangiectasia (HHT).

Methods

The clinical data of one patient with HHT are retrospectively analysed. In addition, we review the relevant literature.

Results

A 32‐year‐old male patient was admitted to the hematology outpatient department of our hospital and presented with intermittent epistaxis for 24 years. In recent years, he was diagnosed with iron deficiency anemia. The nasal endoscopic examination showed telangiectasia at the front of the right‐middle turbinate and the left nasal cavity. He had ENG genetic mutation positivity.

Conclusions

Patients with HHT may suffer from many complications, including bleeding, anemia, iron deficiency, and high‐output heart failure. These patients may have telangiectasias and arteriovenous malformations in various organs.

Surgical management of a congenital arteriovenous fistula of the forearm

Congenital arteriovenous fistula (AVF) is a rare vascular disease, which may occur anywhere in the body. The forearm is a very rare location. Clinical manifestations are not very specific and can vary from an asymptomatic fistula to a life-threatening congestive heart failure. Although embolization can be an alternative treatment for AVF of the forearm, surgery is still considered as the standard treatment. Herein, we report the case of a 7-year-old boy with a congenital AVF between the radial artery and the superficial cephalic vein in the forearm without any dysmorphic features treated surgically.

Pulmonary Arteriovenous Malformations: What the Interventional Radiologist Should Know

Pulmonary arteriovenous malformations (PAVMs) are abnormal connections between the pulmonary artery and pulmonary vein bypassing the normal capillary bed causing a right-to-left shunt. The majority (80-90%) of PAVMs are associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with symptoms of hypoxia, shortness of breath, migraines, sequelae of paradoxical embolization, or rupture. Transcatheter embolization has become the standard of care. This article will review the clinical presentation, workup, genetics, imaging findings, embolization, complications, and follow-up for patients with PAVMs.

A Novel Splicing Mutation in the ACVRL1/ALK1 Gene as a Cause of HHT2

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare disorder of vascular development. Common manifestations include epistaxis, telangiectasias and arteriovenous malformations in multiple organs. Different deletions or nonsense mutations have been described in the ENG (HHT1) or ACVRL1/ALK1 (HHT2) genes, all affecting endothelial homeostasis. A novel mutation in ACVRL1/ALK1 has been identified in a Peruvian family with a clinical history compatible to HHT. Subsequently, 23 DNA samples from oral exchanges (buccal swaps) of the immediate family members were analyzed together with their clinical histories. A routine cDNA PCR followed by comparative DNA sequencing between the founder and another healthy family member showed the presence of the aforementioned specific mutation. The single mutation detected (c.525 + 1G > T) affects the consensus splice junction immediately after exon 4, provokes anomalous splicing and leads to the inclusion of intron IV between exons 4 and 5 in the ACVRL1/ALK1 mRNA and, therefore, to ALK1 haploinsufficiency. Complete sequencing determined that 10 of the 25 family members analyzed were affected by the same mutation. Notably, the approach described in this report could be used as a diagnostic technique, easily incorporated in clinical practice in developing countries and easily extrapolated to other patients carrying such a mutation.

Molecular Pathways and Possible Therapies for Head and Neck Vascular Anomalies

Vascular Anomalies are a heterogenous group of vascular lesions that can be divided, according to the International Society for the Study of Vascular Anomalies Classification, into two main groups : Vascular Tumors and Vascular Malformations. Vascular Malformations can be further subdivided into slow-flow and fast-flow malformations. This clinical and radiological classification allows for a better understanding of vascular anomalies and aims to offer a more precise final diagnosis. Correct diagnosis is essential to propose the best treatment, which traditionally consists of surgery, embolization or sclerotherapy. Since a few years, medical treatment has become an important part of multidisciplinary treatment. Genetic and molecular knowledge of vascular anomalies are increasing rapidly and opens the door for a molecular classification of vascular anomalies according to the underlying pathways involved. The main pathways seem to be: PI3K/AKT/mTOR (PIKopathies) and RAS/RAF/MEK/ERK (RASopathies). Knowing the underlying molecular cascades allows us to use targeted medical therapies. The first part of this article aims to review the vascular anomalies seen in the head and neck region and their underlying molecular causes and involved pathways. The second part will propose an overview of the available targeted therapies based on the affected molecular cascade. This article summarizes theragnostic treatments available in vascular anomalies.

Distribution of Cerebrovascular Phenotypes According to Variants of the ENG and ACVRL1 Genes in Subjects with Hereditary Hemorrhagic Telangiectasia

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder caused, in more than 80% of cases, by mutations of either the endoglin (ENG) or the activin A receptor-like type 1 (ACVRL1) gene. Several hundred variants have been identified in these HHT-causing genes, including deletions, missense and nonsense mutations, splice defects, duplications, and insertions. In this study, we have analyzed retrospectively collected images of magnetic resonance angiographies (MRA) of the brain of HHT patients, followed at the HHT Center of our University Hospital, and looked for the distribution of cerebrovascular phenotypes according to specific gene variants. We found that cerebrovascular malformations were heterogeneous among HHT patients, with phenotypes that ranged from classical arteriovenous malformations (AVM) to intracranial aneurysms (IA), developmental venous anomalies (DVA), and cavernous angiomas (CA). There was also wide heterogeneity among the variants of the ENG and ACVRL1 genes, which included known pathogenic variants, variants of unknown significance, variants pending classification, and variants which had not been previously reported. The percentage of patients with cerebrovascular malformations was significantly higher among subjects with ENG variants than ACVRL1 variants (25.0% vs. 13.1%, p < 0.05). The prevalence of neurovascular anomalies was different among subjects with different gene variants, with an incidence that ranged from 3.3% among subjects with the c.1231C > T, c.200G > A, or c.1120C > T missense mutations of the ACVRL1 gene, to 75.0% among subjects with the c.1435C > T missense mutation of the ACVRL1 gene. Further studies and larger sample sizes are required to confirm these findings.

The Role of Propranolol as a Repurposed Drug in Rare Vascular Diseases

Rare Diseases (RD) are defined by their prevalence in less than 5 in 10,000 of the general population. Considered individually, each RD may seem insignificant, but together they add up to more than 7000 different diseases. Research in RD is not attractive for pharmaceutical companies since it is unlikely to recover development costs for medicines aimed to small numbers of patients. Since most of these diseases are life threatening, this fact underscores the urgent need for treatments. Drug repurposing consists of identifying new uses for approved drugs outside the scope of the original medical indication. It is an alternative option in drug development and represents a viable and risk-managed strategy to develop for RDs. In 2008, the “off label” therapeutic benefits of propranolol were described in the benign tumor Infantile Hemangioma. Propranolol, initially prescribed for high blood pressure, irregular heart rate, essential tremor, and anxiety, has, in the last decade, shown increasing evidence of its antiangiogenic, pro-apoptotic, vasoconstrictor and anti-inflammatory properties in different RDs, including vascular or oncological pathologies. This review highlights the finished and ongoing trials in which propranolol has arisen as a good repurposing drug for improving the health condition in RDs.

A Rare Case of Hereditary Hemorrhagic Telangiectasia: A Case Report

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a very rare autosomal dominant genetic disorder that leads to abnormal blood vessel formation in the skin, mucus membranes (called telangiectasia), and organs such as the lung, liver, and brain. It occurs due to a mutation in one of the ACVRL1, ENG, and SMAD4 genes, which code for the formation of blood vessels. The most common symptom is recurring nosebleed (epistaxis; due to rupture of nasal mucosal telangiectasia), which begins in childhood and affects about 90-95% of people with HHT. Other common signs and symptoms include punctate, linear, or splinter-like telangiectasias on the upper body, oral mucosa, or nail beds, gastrointestinal bleeding, and iron deficiency anemia. The diagnostic criteria currently in use are the Curaçao criteria. The diagnosis is made by clinical screening (e.g., history and physical exam), baseline investigations (complete blood count, hemoglobin, hematocrit, and ferritin level), genetic testing, and detailed medical imaging to detect visceral arteriovenous malformations (AVMs) such as esophagogastroduodenoscopy, colonoscopy, multiphase contrast CT, computed tomography angiography (CTA or CT Angio), magnetic resonance angiography (MRA), chest X-ray, Doppler ultrasonography, liver biopsy, and cerebral angiography. Management includes intravenous iron therapy or blood transfusion, antifibrinolytics (e.g tranexamic acid), ablation therapies (e.g. laser treatment, radiofrequency ablation, electrosurgery, sclerotherapy, and argon plasma coagulation), and systemic anti-angiogenic agents (e.g. thalidomide, bevacizumab). In this report, we present the case of a 22-year-old man from Swabi, Pakistan, with a history of recurrent epistaxis (nosebleed) from childhood, who presented with multiple episodes of melena (blood in stool), fatigue, palpitation, and iron deficiency anemia for five years. Multiple esophagogastroduodenoscopies (OGDs) and colonoscopies were done over the years, which showed AVM in the antrum and fundus of the stomach, duodenum, and colon, and a diagnosis of HHT was made. CTA and exploratory laparotomy showed ileal loop hemangiomas. He was managed with multiple blood transfusions, argon plasma coagulation (APC) for the AVMs, oral thalidomide, and steroids. Despite therapy, the patient had intermittent episodes of blood in stool and low blood counts. During his stay in Hayatabad Medical Complex (HMC), the patient was managed with high-frequency blood transfusion and bevacizumab (systemic anti-angiogenic agent). A dramatic reduction in the number of required transfusions and improvement in the patient's bloodlines and symptoms was noted. This case highlights the importance of endoscopic methods for the timely diagnosis of HHT and its management with intravenous bevacizumab.

Endoglin Wild Type and Variants Associated With Hereditary Hemorrhagic Telangiectasia Type 1 Undergo Distinct Cellular Degradation Pathways

Endoglin, also known as cluster of differentiation 105 (CD105), is an auxiliary receptor in the TGFβ signaling pathway. It is predominantly expressed in endothelial cells as a component of the heterotetrameric receptor dimers comprising type I, type II receptors and the binding ligands. Mutations in the gene encoding Endoglin (ENG) have been associated with hereditary hemorrhagic telangiectasia type 1 (HHT1), an autosomal dominant inherited disease that is generally characterized by vascular malformation. Secretory and many endomembrane proteins synthesized in the Endoplasmic reticulum (ER) are subjected to stringent quality control mechanisms to ensure that only properly folded and assembled proteins are trafficked forward through the secretory pathway to their sites of action. We have previously demonstrated that some Endoglin variants causing HHT1 are trapped in the ER and fail to traffic to their normal localization in plasma membrane, which suggested the possible involvement of ER associated protein degradation (ERAD) in their molecular pathology. In this study, we have investigated, for the first time, the degradation routes of Endoglin wild type and two mutant variants, P165L and V105D, and previously shown to be retained in the ER. Stably transfected HEK293 cells were treated with proteasomal and lysosomal inhibitors in order to elucidate the exact molecular mechanisms underlying the loss of function phenotype associated with these variants. Our results have shown that wild type Endoglin has a relatively short half-life of less than 2 hours and degrades through both the lysosomal and proteasomal pathways, whereas the two mutant disease-causing variants show high stability and predominantly degrades through the proteasomal pathway. Furthermore, we have demonstrated that Endoglin variants P165L and V105D are significantly accumulated in HEK293 cells deficient in HRD1 E3 ubiquitin ligase; a major ERAD component. These results implicate the ERAD mechanism in the pathology of HHT1 caused by the two variants. It is expected that these results will pave the way for more in-depth research studies that could provide new windows for future therapeutic interventions.

Nonmalignant Features Associated with Inherited Colorectal Cancer Syndromes-Clues for Diagnosis

Simple Summary

Familiarity with nonmalignant features and comorbidities of cancer predisposition syndromes may raise awareness and assist clinicians in the diagnosis and interpretation of molecular test results. Genetic predisposition to colorectal cancer (CRC) should be suspected mainly in young patients, in patients with significant family histories, multiple polyps, mismatch repair-deficient tumors, and in association with malignant or nonmalignant comorbidities. The aim of this review is to describe the main nonmalignant comorbidities associated with selected CRC predisposition syndromes that may serve as valuable diagnostic clues for clinicians and genetic professionals.

Abstract

Genetic diagnosis of affected individuals and predictive testing of their at-risk relatives, combined with intensive cancer surveillance, has an enormous cancer-preventive potential in these families. A lack of awareness may be part of the reason why the underlying germline cause remains unexplained in a large proportion of patients with CRC. Various extracolonic features, mainly dermatologic, ophthalmic, dental, endocrine, vascular, and reproductive manifestations occur in many of the cancer predisposition syndromes associated with CRC and polyposis. Some are mediated via the WNT, TGF-β, or mTOR pathways. However the pathogenesis of most features is still obscure. Here we review the extracolonic features of the main syndromes, the existing information regarding their prevalence, and the pathways involved in their pathogenesis. This knowledge could be useful for care managers from different professional disciplines, and used to raise awareness, enable diagnosis, and assist in the process of genetic testing and interpretation.

Imaging to intervention: a review of what the Interventionalist needs to Know about Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a disorder that affects 1 in 5000-10,000 people worldwide and can result in devastating complications such as cerebral abscess, stroke, massive hemorrhage, and even death. HHT is an autosomal dominant disorder that leads to the formation of abnormal communication between the arteries and veins with a resultant spectrum of vascular anomalies. The disorder affects many organ systems and thus requires a dedicated multidisciplinary approach. Interventional radiologists are vital members of this team providing expertise not only in disease management, but in complex embolotherapy, helping to maintain the health of these patients. This article reviews clinical manifestations, screening guidelines, diagnostic criteria, and endovascular management of HHT.