Pleomorphic Parotid Adenoma in a Child Affected with Cri du Chat Syndrome: Clinical, Cytogenetic, and Molecular Analysis.

Salivary gland pleomorphic adenoma (SGPA) is the most common type of benign epithelial tumor; it is observed more commonly in females (with a female-to-male ratio of 1.43:1), and the age at diagnosis ranges between 40 and 59 years, with only 2% of cases diagnosed before age 18. Cri du Chat (CdC) is a rare syndrome caused by deletions of various sizes in the short arm of chromosome 5. Tumors in CdC patients are extremely rare: in Danish, Spanish, Australian, and Japanese groups of cases, no tumors have been reported, while a few cases have been described among 321 CdC patients collected in Italy and Germany. These cases all involve tumors that appear at a young age. We here report the case of a parotid pleomorphic adenoma in an 8-year-old boy with CdC. Exome analysis did not identify variants certainly significant for the development of SGPA. A CGH array, analyzed both in peripheral blood and tumor samples, failed to recognize anomalies previously associated with SGPA but identified a de novo duplication in 7p15.2, which contains part of a gene, SKAP2, in which the increased copy number is associated with the development of a different type of tumor such as pancreatic duct adenocarcinoma. The assumption that the duplication in 7p15.2 is relevant for the development of SGPA in our patient implies that CGH array studies must be included early in life in routine work-ups of CdC to identify CNVs with possible pathogenic roles for tumor development. This is particularly also relevant in relation to the severely impaired possibility for patients with CdC to report discomfort or pain related to tumor development. Constitutional CNVs in addition to the deletion in 5p should also be extensively studied to verify if their presence in some patients could explain why, in these cases, tumors develop at an age younger than expected.

Nasal Endoscopy in the Clinical Diagnosis of Hereditary Hemorrhagic Telangiectasia.

OBJECTIVES: To evaluate the role of nasal endoscopy for early clinical diagnosis of hereditary hemorrhagic telangiectasia (HHT) in children and to investigate the characteristics of epistaxis and mucocutaneous telangiectases in our pediatric population. STUDY DESIGN: From May 2016 to December 2019, a cross-sectional observational study was conducted, recruiting children aged 2-18 years with a parent affected by HHT. To identify the Curaçao criteria, all children underwent collection of clinical history, mucocutaneous examination, and nasal endoscopy. The clinical data were then compared with the genetic data acquired subsequently. RESULTS: Seventy children (median age, 10.8 years) were included. All underwent nasal endoscopy without complications. Forty-six children were positive by genetic testing; of these, 26 % had skin and oral telangiectases and 91 % had nasal telangiectases. The diagnostic sensitivity of the Curaçao criteria increased from 28 % (95 % CI, 16%-43 %) to 85 % (95 % CI, 71%-94 %; P < .0001) when the nasal telangiectases were included. CONCLUSIONS: The magnified and complete endoscopic view of the nasal cavities proved useful in increasing the diagnostic sensitivity of the Curaçao criteria. Such an examination turned out to be feasible and safe. For this reason, we believe that nasal endoscopy should be included in the diagnostic assessment of pediatric patients with suspected HHT.

Shwachman-Diamond syndrome with clonal interstitial deletion of the long arm of chromosome 20 in bone marrow: haematological features, prognosis and genomic instability.

In Shwachman-Diamond syndrome (SDS), deletion of the long arm of chromosome 20, del(20)(q), often acquired in bone marrow (BM), may imply a lower risk of developing myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML), due to the loss of the EIF6 gene. The genes L3MBTL1 and SGK2, also on chromosome 20, are in a cluster of imprinted genes, and their loss implies dysregulation of BM function. We report here the results of array comparative genomic hybridization (a-CGH) performed on BM DNA of six patients which confirmed the consistent loss of EIF6 gene. Interestingly, array single nucleotide polymorphisms (SNPs) showed copy neutral loss of heterozygosity for EIF6 region in cases without del(20)(q). No preferential parental origin of the deleted chromosome 20 was detected by microsatellite analysis in six SDS patients. Our patients showed a very mild haematological condition, and none evolved into BM aplasia or MDS/AML. We extend the benign prognostic significance of del(20)(q) and loss of EIF6 to the haematological features of these patients, consistently characterized by mild hypoplastic BM, no or mild neutropenia, anaemia and thrombocytopenia. Some odd results obtained in microsatellite and SNP-array analysis demonstrate a peculiar genomic instability, in an attempt to improve BM function through the acquisition of the del(20)(q).

Endoscopic evaluation of gastrointestinal tract in patients with hereditary hemorrhagic telangiectasia and correlation with their genotypes.

PURPOSE: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal-dominant vascular dysplasia characterized by telangiectases and arteriovenous malformations. Three causative genes are known: ENG (HHT-1), ACVRL1 (HHT-2), and SMAD4 (mutated in HHT in association with juvenile polyposis). Gastrointestinal bleeding is the most common symptom after epistaxis. The stomach and the duodenum are the main gastrointestinal sites of telangiectases. Our aim was to explore gastrointestinal tract of consecutive HHT patients to assess distribution, number, size, and type of telangiectases in relation to genotype. METHODS: HHT patients underwent gastroduodenoscopy, video capsule endoscopy, and colonoscopy. Molecular analysis of ENG and ACVRL1 was performed to identify the disease-causing mutation. RESULTS: Twenty-two patients (13 men; mean age: 59 ± 9 years) were analyzed: 7 with HHT-1, 13 with HHT-2, and 2 undefined. Gastrointestinal telangiectases were identified as follows: at gastroduodenoscopy in 86% of HHT-1 patients and in 77% of HHT-2 patients, at video capsule endoscopy in all HHT-1 patients and in 84% of HHT-2 patients, and at colonoscopy in 1 patient for each group. HHT-1 showed multiple telangiectases with a higher prevalence, more relevant in the duodenum. CONCLUSION: Our data demonstrate extensive involvement of the gastrointestinal tract with a more severe association in HHT-1. Gastroduodenoscopy provides significant information on gastrointestinal involvement, and video capsule endoscopy may be added in selected patients. Colonic polyps/adenomas were identified as occasional findings.

Hereditary Hemorrhagic Telangiectasia in Pediatric Age: Focus on Genetics and Diagnosis.

Hereditary Hemorrhagic Telangiectasia (HHT) or Rendu-Osler-Weber Syndrome (ROW) is an autosomal dominant vascular disease, with an estimated prevalence of 1:5000. Genes associated with HHT are ACVRL1, ENG, SMAD4, and GDF2, all encoding for proteins involved in the TGFß/BMPs signaling pathway. The clinical diagnosis of HHT is made according to the "Curaçao Criteria," based on the main features of the disease: recurrent and spontaneous epistaxis, muco-cutaneous telangiectases, arteriovenous malformations in the lungs, liver, and brain, and familiarity. Since the clinical signs of HHT can be misinterpreted, and the primary symptom of HHT, epistaxis, is common in the general population, the disease is underdiagnosed. Although HHT exhibits a complete penetrance after the age of 40, young subjects may also present symptoms of the disease and are at risk of severe complications. Here we review the literature reporting data from clinical, diagnostic, and molecular studies on the HHT pediatric population.

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.

Endoglin and Systemic Sclerosis: A PRISMA-driven systematic review.

Background: Systemic Sclerosis (SSc) is a rare autoimmune disease whose pathogenesis is still poorly understood. The Transforming Growth Factor ß superfamily is considered pivotal and a crucial role has been suggested for the type III receptor, Endoglin (ENG). The aim of this systematic review is to investigate and combine the current clinical and molecular available data, to suggest novel hints for further studies. Methods: We followed PRISMA guidelines; the search was performed on three databases (MEDLINE, Web of Science, Embase) in date November 2nd, 2021. Subsequent to the exclusion of duplicates, we applied as inclusion criteria: 1. focus on the relationship between ENG and SSc; 2. English language. As exclusion criteria: 1. ENG exclusively as a cellular biomarker; 2. no focus on ENG-SSc relationship; 3. review articles and 4. abstracts that did not add novel data. Eligibility was assessed independently by each author to reduce biases. We divided records into clinical and molecular works and subgrouped them by their study features and aim. Results: We selected 25 original papers and 10 conference abstracts. Molecular studies included 6 articles and 4 abstracts, whereas clinical studies included 17 articles and 6 abstracts; 2 articles presented both characteristics. Molecular studies were focussed on ENG expression in different cell types, showing an altered ENG expression in SSc-affected cells. Clinical studies mainly suggested that different disease phenotypes can be related to peculiar disregulations in soluble ENG concentrations. Discussion: Concerning the possible limits of our search, boolean operators in our strings might have been uneffective. However, the use of different strings in different databases should have reduced this issue at a minimum. Another bias can be represented by the selection step, in which we excluded many articles based on the role of Endoglin as a histological vascular marker rather than a signaling receptor. We tried to reduce this risk by performing the selection independently by each author and discussing disagreements. Our systematic review pointed out that ENG has a pivotal role in activating different TGFß-stimulated pathways that can be crucial in SSc pathogenesis and progression.

Hereditary hemorrhagic telangiectasia: First demonstration of a founder effect in Italy; the ACVRL1 c.289_294del variant originated in the country of Bergamo 200 years ago.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder, affecting 1:5000 individuals worldwide. All the genes associated to the disease (ENG, ACVRL1, SMAD4, GDF2) belong to the TGF-ß/BMPs signaling pathway. We found 19 HHT unrelated families, coming from a Northern Italy region and sharing the ACVRL1 in-frame deletion c.289_294del (p.H97_N98). METHODS: To test the hypothesis of a founder effect, we analyzed 88 subjects from 19 families (66 variant carriers, showing clinical signs of HHT, and 22 non-carriers, unaffected) using eight microsatellite markers within 3.7 Mb around the ACVRL1 locus. After the haplotype reconstruction, age estimation of the variant was carried out. RESULTS: We observed a common disease haplotype in 16/19 families, while three families showed evidence of recombination around the ACVRL1 locus. The subsequent age estimation analyses suggested that the mutation occurred about 8 generations ago, corresponding to about 200 years ago. We also present novel in silico and modeling data supporting the variant pathogenicity: the deletion alters the protein stability and removes the unique extracellular glycosylation site. CONCLUSION: We have demonstrated, for the first time, a "founder effect" for a HHT pathogenic variant in Italy.

Natural history and outcome of hepatic vascular malformations in a large cohort of patients with hereditary hemorrhagic teleangiectasia.

BACKGROUND: Hereditary hemorrhagic telangiectasia is a genetic disease characterized by teleangiectasias involving virtually every organ. There are limited data in the literature regarding the natural history of liver vascular malformations in hemorrhagic telangiectasia and their associated morbidity and mortality. AIM: This prospective cohort study sought to assess the outcome of liver involvement in hereditary hemorrhagic telangiectasia patients. METHODS: We analyzed 16 years of surveillance data from a tertiary hereditary hemorrhagic telangiectasia referral center in Italy. We considered for inclusion in this study 502 consecutive Italian patients at risk of hereditary hemorrhagic telangiectasia who presented at the hereditary hemorrhagic telangiectasia referral center and underwent a multidisciplinary screening protocol for the diagnosis of hereditary hemorrhagic telangiectasia. Of the 502 individuals assessed in the center, 154 had hepatic vascular malformations and were the subject of the study; 198 patients with hereditary hemorrhagic telangiectasia and without hepatic vascular malformations were the controls. Additionally, we report the response to treatment of patients with complicated hepatic vascular malformations. RESULTS: The 154 patients were included and followed for a median period of 44 months (range 12-181); of these, eight (5.2%) died from VM-related complications and 39 (25.3%) experienced complications. The average incidence rates of death and complications were 1.1 and 3.6 per 100 person-years, respectively. The median overall survival and event-free survival after diagnosis were 175 and 90 months, respectively. The rate of complete response to therapy was 63%. CONCLUSIONS: This study shows that substantial morbidity and mortality are associated with liver vascular malformations in hereditary hemorrhagic telangiectasia patients.

BMPR2 mutations and response to inhaled or parenteral prostanoids: a case series.

Whether mutations in the BMPR2 gene may influence the response to PAH-specific therapies has not yet been investigated. In this study, in 13 idiopathic, heritable or anorexigen-associated PAH patients, in whom treatment escalation was performed by adding a prostanoid, a greater haemodynamic improvement was observed in BMPR2-negative than in BMPR2-positive patients.

Endoscopic surgical treatment of epistaxis in hereditary haemorrhagic telangiectasia: our experience.

OBJECTIVES: Hereditary haemorrhagic telangiectasia (HHT) is a rare autosomal dominant disease characterised by epistaxis. Surgical procedures for epistaxis vary from diathermocoagulation to nasal closure. The aim of this paper is to report our experience in endoscopic surgical management of epistaxis in HHT patients. METHODS: This is a descriptive, longitudinal study carried out at the Otorhinolaryngology Department of IRCCS Policlinico San Matteo in Pavia, a reference centre for the treatment and diagnosis of HHT. We retrospectively evaluated HHT patients who underwent surgery for epistaxis from 1996 to 2015, including only those treated with endoscopic surgery. RESULTS: Among the 591 patients hospitalised and screened for HHT, 323 (54.7%) underwent endoscopic surgery for epistaxis, for a total of 679 procedures. General anaesthesia was used in 77.2% of procedures; argon plasma coagulation was the instrument of choice in the majority of patients, followed by lasers and quantum molecular resonance technology. CONCLUSIONS: We report one of the largest cohorts undergoing endoscopic treatment of epistaxis in HHT patients. This mini-invasive surgical treatment allowed us to control epistaxis without major complications and nasal packaging and can be repeated over time. For these reasons, we recommend it as first choice in case of epistaxis in HHT patients.

Overlapping spectra of SMAD4 mutations in juvenile polyposis (JP) and JP-HHT syndrome.

Juvenile polyposis (JP) and hereditary hemorrhagic telangiectasia (HHT) are clinically distinct diseases caused by mutations in SMAD4 and BMPR1A (for JP) and endoglin and ALK1 (for HHT). Recently, a combined syndrome of JP-HHT was described that is also caused by mutations in SMAD4. Although both JP and JP-HHT are caused by SMAD4 mutations, a possible genotype:phenotype correlation was noted as all of the SMAD4 mutations in the JP-HHT patients were clustered in the COOH-terminal MH2 domain of the protein. If valid, this correlation would provide a molecular explanation for the phenotypic differences, as well as a pre-symptomatic diagnostic test to distinguish patients at risk for the overlapping but different clinical features of the disorders. In this study, we collected 19 new JP-HHT patients from which we identified 15 additional SMAD4 mutations. We also reviewed the literature for other reports of JP patients with HHT symptoms with confirmed SMAD4 mutations. Our combined results show that although the SMAD4 mutations in JP-HHT patients do show a tendency to cluster in the MH2 domain, mutations in other parts of the gene also cause the combined syndrome. Thus, any mutation in SMAD4 can cause JP-HHT. Any JP patient with a SMAD4 mutation is, therefore, at risk for the visceral manifestations of HHT and any HHT patient with SMAD4 mutation is at risk for early onset gastrointestinal cancer. In conclusion, a patient who tests positive for any SMAD4 mutation must be considered at risk for the combined syndrome of JP-HHT and monitored accordingly.

Characterization of a mutation in the zona pellucida module of Endoglin that causes Hereditary Hemorrhagic Telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is a vascular rare disease characterized by nose and gastrointestinal bleeding, skin and mucosa telangiectasias, and arteriovenous malformations in internal organs. HHT shows an autosomal dominant inheritance and a worldwide prevalence of approximately 1:5000 individuals. In >80% of patients, HHT is caused by mutations in either ENG (HHT1) or ACVRL1 (HHT2) genes, which code for the membrane proteins Endoglin and Activin A Receptor Type II-Like Kinase 1 (ALK1), respectively, both belonging to the TGF-ß/BMP signaling pathway. In this work, we describe a novel mutation in exon 9 of ENG (c.1145 G > A) found in five affected members of a family, all of them with characteristic symptoms of HHT. This mutation involves Cys382 residue of the Endoglin protein (p.Cys382 > Tyr) in the zona pellucida (ZP) module of its extracellular region. This is a critical residue involved in a conserved intrachain disulphide bond and in the correct folding of the protein. In fact, transfection studies in human cells using Endoglin expression vectors demonstrated that the p.Cys382 > Tyr mutation results in a marked reduction in the levels of the Endoglin protein. These results demonstrate the pathogenic role for this variant in HHT1 and confirm the key function of Cys382 in Endoglin expression.

Hereditary hemorrhagic telangiectasia: evidence for regional founder effects of ACVRL1 mutations in French and Italian patients.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease characterized by widespread arteriovenous malformations and caused by mutations in two major genes: ENG and ACVRL1. Two decades ago, a French epidemiological study pointed out that its prevalence was higher than previously thought and that its distribution varied greatly from one area to another, one of the highest concentrations of patients being found in the Haut-Jura mountains. Although germline mutations are usually family specific, some of them have been reported in unrelated patients, especially for ACVRL1. We performed haplotype analysis of 116 French and Italian patients carrying 13 ACVRL1 different mutations. For five of these mutations, we estimated the age of the most recent common ancestors (MRCAs) using the ESTIAGE program. Most mutations were related to both recurrent mutational events and founder effects with age estimates ranging from 100 to 550 years. The c.1112dupG mutation, which is likely to be responsible for the very high concentration of HHT patients found in the former epidemiological study, probably occurred in one inhabitant of the Haut-Jura Mountains more than three centuries ago. The p.Arg374Gln mutation occurred independently in at least two distinct geographical areas, including the area with the second highest prevalence in the epidemiological study and where the MRCA is rather recent (about 100 years ago). Partially shared haplotypes between French and Italian patients were found for three mutations. This suggests a common origin and a possible diffusion of these mutations from Italy to France.

Interobserver agreement in diagnosing liver involvement in hereditary hemorrhagic telangiectasia by Doppler ultrasound.

The purpose was to evaluate interobserver agreement on Doppler ultrasonographic (US) diagnosis of liver vascular malformations (VMs) in hereditary hemorrhagic teleangiectasia (HHT) and on their severity grading. During the interobserver agreement study, three observers with at least seven years of specific experience using Doppler US for the diagnosis of liver VMs, judged about the presence/absence of liver VMs and their severity on a set of images and videoclips. Interobserver agreement was estimated with kappa statistics. One-hundred ten cases were reviewed during interobserver study (80 cases with liver VMs, 30 without). Very good kappa values of the interobserver agreement were found for all pairs concerning the distinction between presence and absence of hepatic VMs. All observers demonstrated excellent sensitivity and specificity in identifying hepatic VMs, with their respective areas under the curve ranging from 0.97 to 0.99. Interobserver agreement among the three investigators in staging the hepatic VMs in HHT patients was moderate (Kendall's coefficient of concordance = 0.26). Study results indicate that Doppler US diagnosis of liver VMs in HHT has a high degree of agreement among ultrasonographers; a moderate agreement was found regarding severity staging.

Functional analysis of a novel ENG variant in a patient with hereditary hemorrhagic telangiectasia (HHT) identifies a new Sp1 binding-site.

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare disease, with an autosomal dominant inheritance and a worldwide incidence of about 1: 5000 individuals. In >80% of patients, HHT is caused by mutations in either ENG or ACVRL1, which code for ENDOGLIN and Activin A Receptor Type II-Like Kinase 1 (ALK1), belonging to the TGF-ß/BMP signalling pathway. Typical HHT clinical features are mucocutaneous telangiectases, arteriovenous malformations, spontaneous and recurrent epistaxis, as well as gastrointestinal bleedings. An additional, but less frequent, clinical manifestation in some HHT patients is the presence of Pulmonary Arterial Hypertension (PAH). The aim of this work is to describe the functional role of a novel ENG intronic variant found in a patient affected by both HHT and PAH, in order to assess whether it has a pathogenic role. We proved that the variant lies in a novel binding-site for the transcription factor Sp1, known to be involved in the regulation of ENG and ACVRL1 transcription. We confirmed a pathogenic role for this intronic variant, as it significantly reduces ENG transcription by affecting this novel Sp1 binding-site.

Different forms of pulmonary hypertension in a family with clinical and genetic evidence for hereditary hemorrhagic teleangectasia type 2.

Hereditary hemorrhagic telangiectasia (HTT) is an autosomal dominant disease, most frequently caused by a mutation in either ENG or ACVRL1, which can be associated with pulmonary arterial hypertension (PAH). In this report, we describe a new unpublished ACVRL1 mutation segregating in three members of the same family, showing three different types of pulmonary hypertension (PH) in the absence of BMPR2 mutations. The first patient has a form of heritable PAH (HPAH) in the absence of hepatic arteriovenous malformations (AVMs); the second one has a severe form of portopulmonary hypertension (PoPAH) associated with multiple hepatic AVMs; the third one has hepatopulmonary syndrome (HPS) with numerous hepatic arteriovenous fistulas and a form of post-capillary PH due to high cardiac output. In summary, a single mutation in the ACVRL1 gene can be associated, in the same family, with an extreme phenotypic variability regarding not only the clinical presentation of HHT but also the type of PH in the absence of BMPR2 mutations. More studies are needed to evaluate if this variability can be explained by the presence of additional variants in other genes relevant for the pathogenesis of HHT.

Epidemiology and clinical aspects of Werner's syndrome in North Sardinia: description of a cluster.

Werner syndrome (WS, MIM#277700) is a very rare autosomal recessive disorder. WS clinical signs include altered distribution of subcutaneous fat, juvenile bilateral cataracts, a mask-like face and bird-like nose, trophic ulcers of the feet, diabetes mellitus, and premature atherosclerosis. The habitus is characteristic, with short stature, stocky trunk and slender extremities. WS frequency has been roughly estimated to be 1: 100,000 in Japan and 1: 1,000,000-1: 10,000,000 outside of Japan. The only exception to the latter data can be seen in the clustering of WS in Sardinia. Since 2001, 5 new cases have been observed: 4 members of the same family and 1 sporadic case. Therefore, since 1982 the total number of cases described in North Sardinia amounts to 18: 15 are familial (11 members of the same family group) and 3 sporadic. A short clinical description of the 5 new cases is reported.

Fluorescein-guided intraoperative endoscopy in patients with hereditary hemorrhagic telangiectasia: first impressions.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic disease that results in mucocutaneous telangiectasias and arteriovenous visceral malformations. Nasal telangiectasias lead to recurrent epistaxis, which affects up to 96% of patients. Different morphologic classifications and methods of visualization of nasal lesions have been described in the literature. We developed a new method of intraoperative endoscopy based on the intravenous administration of fluorescein. Preliminary data of this technique are reported. METHODS: After the intravenous administration of sodium fluorescein, an intraoperative fluorescein-guided endoscopy was carried out using photographic customized yellow filters on top of a 0-degree, 4-mm endoscope. RESULTS: In 2015, 65 HHT patients underwent surgery for their epistaxis in our institution, and in 7 patients (3 males, 4 females; mean age, 54 years) an intraoperative fluorescein-guided intraoperative nasal endoscopy was performed. No adverse events or complications were observed. CONCLUSION: First impressions regarding the usage of this technique in HHT patients seem to be promising and positive in terms of efficacy and safety. However, further studies with larger cohorts of patients should be performed in order to better investigate the use of this method for diagnostic and surgical purposes in HHT.