遗传性出血性毛细血管扩张症基因突变分析

目的 分析遗传性出血性毛细血管扩张症(hereditary hemorrhagic telangiectasia,HHT)家系ENG、ACVEL1和SMAD4基因突变.方法 收集4个HHT家系临床资料并分析其临床特点,应用直接测序和多重连接探针扩增技术对11例临床确诊及可疑患者的ENG、ACVRL1和SMAD4基因进行突变分析,将结果与HHT基因突变数据库进行对比.结果 家系2先证者及2个妹妹的ENG基因发生了第2外显子c.207G＞A(p.L69L)同义突变、第8外显子c.1004A＞T(p.Q335L)错义突变、ACVRL1基因第7外显子c.817C＞T(L273L)同义突变;家系3先证者及其母亲和弟的ENG基因发生了第8外显子c.1004A＞T(p.Q335L)突变;也检测到家系4先证者及其兄的ENG基因第8外显子c.1004A＞T(p.Q335L)突变.家系1先证者及其他HHT患者,未检测到基因突变.其中ENG基因第8外显子c.1004A＞ T(p.335Q＞L)为新突变,在200名正常对照中也未检测到该突变.结论 HHT具有遗传异质性,ENG基因第8外显子c.1004A＞T(p.Q335L)为HHT新的致病突变.     

BMPR2 mutation in a patient with pulmonary arterial hypertension and suspected hereditary hemorrhagic telangiectasia

Pulmonary arterial hypertension (PAH) and hereditary hemorrhagic telangiectasia (HHT) are distinct clinical entities caused by germline mutations in genes encoding members of the TGFbeta/BMP superfamily: BMPR2 in PAH and ACVRL1, ENG, or SMAD4 in HHT. When PAH and HHT occasionally co-exist within the same family, ACVRL1 mutations predominate. We report a 36-year-old woman initially diagnosed with PAH at age 24. At 35, following massive hemoptysis, multiple pulmonary arteriovenous malformations were discovered, prompting evaluation for HHT. She met the Cura?ao diagnostic criteria for suspected HHT based on additional findings of nasal telangiectases and epistaxis. Mutation analysis of ACVRL1, ENG, and SMAD4 was normal, but a germline nonsense mutation in BMPR2 was identified. This is the first known report of HHT features, particularly pulmonary AVMs, associated with a BMPR2 mutation. It adds further weight to a common molecular pathogenesis in PAH and HHT, and highlights that BMPR2 gene analysis is indicated in patients affected with both HHT and PAH.     

Liver disease in patients with hereditary hemorrhagic telangiectasia

BACKGROUND: Hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber disease, is an autosomal dominant disorder characterized by angiodysplastic lesions (telangiectases and arteriovenous malformations) that affect many organs. Liver involvement in patients with this disease has not been fully characterized. METHODS: We studied the clinical findings and results of hemodynamic, angiographic, and imaging studies in 19 patients with hereditary hemorrhagic telangiectasia and symptomatic liver involvement. RESULTS: We evaluated 14 women and 5 men who ranged in age from 34 to 74 years. All but one of the patients had a hyperdynamic circulation (cardiac index, 4.2 to 7.3 liters per minute per square meter of body-surface area). In eight patients, the clinical findings were consistent with the presence of high-output heart failure. The cardiac index and pulmonary-capillary wedge pressure were elevated in the six patients in whom these measurements were performed. After a median period of 24 months, the condition of three of the eight patients had improved, four were in stable condition with medical therapy, and one had died. Six patients had manifestations of portal hypertension such as ascites or variceal bleeding. The hepatic sinusoidal pressure was elevated in the four patients in whom it was measured. After a median period of 19 months, the condition of two of the six patients had improved, and the other four had died. Five patients had manifestations of biliary disease, such as an elevated alkaline phosphatase level and abnormalities on bile duct imaging. After a median period of 30 months, the condition of two of the five had improved, the condition of one was unchanged, heart failure had developed in one, and one had died after an unsuccessful attempt at liver transplantation. CONCLUSIONS: In patients with hereditary hemorrhagic telangiectasia and symptomatic liver-involvement, the typical clinical presentations include high-output heart failure, portal hypertension, and biliary disease.     

ACVRL1 germinal mosaic with two mutant alleles in hereditary hemorrhagic telangiectasia associated with pulmonary arterial hypertension

Eyries M, Coulet F, Girerd B, Montani D, Humbert M, Lacombe P, Chinet T, Gouya L, Roume J, Axford MM, Pearson CE, Soubrier F. ACVRL1 germinal mosaic with two mutant alleles in hereditary hemorrhagic telangiectasia associated with pulmonary arterial hypertension. Germline mutations in genes encoding members of the transforming growth factor‐β (TGF‐β)/bone morphogenetic protein (BMP) superfamily are causal for two hereditary vascular disorders, hereditary hemorrhagic telangiectasia (HHT) and heritable pulmonary arterial hypertension (PAH). When the two diseases coexist, activin A receptor type II‐like kinase‐1 (ACVRL1) gene mutations are usually identified. We report a remarkable ACVRL1 germinal and somatic mosaicism characterized by the presence of two distinct mutant alleles and a non‐mutant ACVRL1 allele in a woman diagnosed with PAH at the age 40. She also met the Curaçao diagnostic criteria for HHT based on additional findings of telangiectases, epistaxis and arteriovenous malformations. Mutation analysis of ACVRL1 identified two adjacent heterozygous deleterious mutations within exon 10: c.1388del (p.Gly463fsX2) and c.1390del (p.Leu464X) in a region enriched by mutation‐associated DNA motifs. The mother transmitted the c.1388del to one child and the c.1390del to two children confirming germinal mosaicism. Allele‐specific polymerase chain reaction analysis showed that c.1388del is the predominant mutation in lymphocytes of the index case. Haplotype analysis revealed that both mutant alleles have a common chromosomal origin which is distinct from that of the mother's non‐mutant ACVRL1 allele. These distinct mutant alleles in tissues and germline could have arisen by DNA structure‐mediated events occurring in the early stages of the mother's embryogenesis, prior to the segregation of her germline, which ultimately led to the independent transmission of each allele. These highlight the complexity of genomic events occurring during early embryogenesis and the consequences of mutational mosaicism upon pathogenic variability.     

Cost comparison of genetic and clinical screening in families with hereditary hemorrhagic telangiectasia

Endoglin (ENG) and ALK-1 mutations cause hereditary hemorrhagic telangiecstasia (HHT), an autosomal dominant disorder leading to vascular dysplasia in the form of mucocutaneous telangiectasia and visceral arteriovenous malformations (AVMs). We proposed to compare two alternative strategies for management of HHT: screening HHT families with molecular diagnostic tests followed by targeted clinical screening versus conventional clinical screening. A decision analytic model was constructed to compare screening strategies for a hypothetical HHT family. The family consists of 1 index case and 13 relatives. The clinical screening protocol in use at the Canadian HHT Center in Toronto was assumed to be the standard of care. Unit costs for clinical screening (in Canadian dollars) were obtained from the 2003 Ontario Health Insurance Schedule of Benefits. Genetic screening costs were estimated for quantitative multiplex PCR and sequencing of Endoglin (ENG) and ALK-1 genes, as performed at HHT Solutions, Toronto. The genetic screening strategy resulted in a net cost of $4,060 per individual versus $5,975 for the clinical screening strategy. The genetic screening strategy would save $1,915 per family member or $26,810 saved per family. Sensitivity analyses revealed that the genetic screening strategy was cost saving over all plausible ranges of input variables for all hypothetical families tested. We concluded that a genetic screening strategy with targeted clinical screening is more economically attractive than conventional clinical screening and results in a reduction in the number of clinical tests for family members who do not have HHT.     

Hepatolithiasis in hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia is a rare, hereditary fibrovascular dysplasia. We report a case associated with hepatolithiasis. Hepatolithiasis, relatively common in East Asia, is rare in the West. The association of the two conditions has not been previously reported. In this case, vascular malformations in the liver gave rise to arteriovenous and arterioportal fistulas, causing arteriovenous shunting and protal hypertension, respectively. Abnormal blood flow is the proposed mechanism for the hepatic fibrosis and nodular regeneration. Hepatic fibrosis, by causing stenosis of large intrahepatic bile ducts, bile stasis, and secondary infection, is the hypothesized mechanism for calculus formation. Hepatolithiasis ultimately caused death from acute bacterial cholangitis and septicemia.     

Cost savings through molecular diagnosis for hereditary hemorrhagic telangiectasia

PurposeHereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder of vascular development resulting in direct connections between the arterial and venous systems, bypassing capillaries. Symptoms and signs can appear throughout life and marked intrafamilial variability confounds diagnosis based purely on clinical criteria. We set out to determine the impact of genetic testing on the cost of screening for HHT in at-risk relatives.MethodsWe performed economic modeling of idealized pedigrees following two scenarios: repeated clinical screening until an HHT diagnosis could be either affirmed or excluded, and mutation testing in the proband, followed by genetic testing of at-risk relatives and clinical monitoring of only those relatives who test positive for the familial mutation.ResultsBased on actual reimbursement data from our region’s largest health insurer, the molecular diagnostic model saved over $22,000 for a family with four relatives at risk for the initial diagnostic work-up. For a cohort of 100 probands, the total savings for the molecular diagnostic model over a reasonable period of follow-up was greater than $9 million.ConclusionIn this idealized setting in which all probands and at-risk relatives accepted molecular testing, the economic advantages of genetic screening over repeated clinical screening are substantial.Genet Med 2012:14(6):604–610     

Clinical manifestations of patients with GDF2 mutations associated with hereditary hemorrhagic telangiectasia type 5

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant fibrovascular dysplasia caused by mutations in ENG, ACVRL1, and SMAD4. Increasingly, there has been an appreciation for vascular conditions with phenotypic overlap to HHT but which have distinct clinical manifestations and arise from novel or uncharacterized gene variants. This study reported on a cohort of four unrelated probands who were diagnosed with a rare form of GDF2-related HHT5, for which only five prior cases have been described. Two patients harbored heterozygous missense variants not previously annotated as pathogenic (p.Val403Ile; p.Glu355Gln). Clinically, these patients had features resembling HHT1, including cerebrovascular involvement of their disease (first report documenting cerebral involvement of HHT5), but with earlier onset of epistaxis and a unique anatomic distribution of dermal capillary lesions that involved the upper forelimbs, trunk, and head. The other two patients harbored interstitial deletions larger than five megabases between 10q11.22 and 10q11.23 that included GDF2. To our knowledge, this is the first report detailing large genomic deletions leading to HHT5. These patients also demonstrated mucocutaneous capillary dysplasias, including intranasal vascular lesions complicated by childhood-onset epistasis, with a number of extravascular findings related to their 10q11.21q11.23 deletion. In conclusion, patients with GDF2-related HHT may present with a number of unique characteristics that differ from classically reported features of HHT.     

Pulmonary arteriovenous fistulas in hereditary hemorrhagic telangiectasia

We reviewed all available chest X-rays of 95 patients with hereditary hemorrhagic telangiectasia (HHT). The diagnosis of pulmonary arteriovenous fistula (PF) had previously been made in 13 patients, nine of whom had been operated on. Another three cases were found in the review. The 16 patients with HHT and PF came from eight families, one of which contributed seven patients. Median observation time between the first and the latest chest X-ray examination was 11 years (range 1/2-35). Growth of the PF was seen in four patients and spontaneous regression in one. Four of the 16 patients with PF had symptoms consistent with cerebral embolism, while only two of the 79 patients without PF had such symptoms. This study is part of an epidemiological investigation of HHT--to our knowledge not carried out before. The calculated period prevalence of simultaneous HHT and PF in the decade 1964-74 in the county of Fyn (429 207 inhabitants) was 2.6 per 100 000.     

Plasma level and tissue expression of angiogenic factors in patients with hereditary hemorrhagic telangiectasia

The value of angiogenic factors interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) was determined in patients with hereditary hemorrhagic telangiectasia (HHT) to evaluate their role in HHT pathogenesis. IL-8 and VEGF were measured in plasma of 41 HHT patients and healthy controls by ELISA technique. In both groups, the IL-8 and VEGF tissue expression in cryostat sections of the nasal mucosa were then compared. VEGF plasma levels were significantly increased in HHT patients compared to healthy controls. In contrast, the IL-8 plasma levels in both groups did not show any significant difference. Compared to healthy controls, HHT tissue samples showed a weak IL-8 staining, whereas the VEGF staining was very strong. The plasma levels of VEGF and IL-8 could not be correlated to the patients' clinicopathological findings. Additionally to the angiogenic pro-inflammatory cytokine IL-8, the angiogenic factor VEGF seems to play a major role in HHT pathogenesis.     

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

PurposeHereditary 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.MethodsHHT patients underwent gastroduodenoscopy, video capsule endoscopy, and colonoscopy. Molecular analysis of ENG and ACVRL1 was performed to identify the disease-causing mutation.ResultsTwenty-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.ConclusionOur 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.Genet Med16 1, 3–10.     

Pulmonary capillary hemangiomatosis arising in hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is an autosomal dominant inherited disease characterized by epistaxis, telangiectases, and visceral arteriovenous malformations that can lead to hemorrhage and other complications. We report the case of a 56-year-old female patient with HHT and pulmonary hypertension who died with intractable pulmonary and gastrointestinal bleeding. Autopsy revealed vascular malformations in the lungs, gastrointestinal tract, liver, spleen, and brain. Capillary proliferations in the pulmonary alveolar walls, characteristic of pulmonary capillary hemangiomatosis, were identified, as was evidence of pulmonary hypertensive arteriopathy. To our knowledge, this is the first report of pulmonary capillary hemangiomatosis arising in HHT. The histopathologic findings of HHT and pulmonary capillary hemangiomatosis are reviewed, and a possible role for diminished capillary expression of endothelial nitric oxide synthase is discussed.     

Nodular transformation of the liver in hereditary hemorrhagic telangiectasia

A case of hereditary hemorrhagic telangiectasia with prominent nodular transformation of the liver is described. The presence of enlarged arteries was documented morphometrically. Artery-to-portal vein shunts were also found. The association of abnormal vessels with hepatic nodules supports the hypothesis that abnormalities of blood flow cause nodular transformation. Nodular transformation may be the lesion that has heretofore been termed cirrhosis hepatis telangiectasia or atypical cirrhosis.     

Genotype-phenotype correlation in hereditary hemorrhagic telangiectasia: mutations and manifestations

Hereditary hemorrhagic telangiectasia (HHT) is a genetically heterogeneous vascular dysplasia with multiple telangiectases and arteriovenous malformations and it is caused by mutations in endoglin gene (ENG) (HHT1) and activin A receptor type II-like 1 gene (ACVRL1) (HHT2). We evaluated 111 patients with HHT from 34 families by history, examination, screening for vascular malformations, and sequencing of both genes. We found mutations in 26 of the 34 kindreds (76%) analyzed-54% were in ENG and 46% were in ACVRL1. Mutations in ACVRL1 cluster largely in exons 7 and 8, but ENG mutations were widely distributed within that gene. We found that epistaxis had an earlier onset in patients with HHT1 than those with HHT2, but the severity by middle ages was similar. Pulmonary arteriovenous malformations were more frequent and on the average of larger size in HHT1. Hepatic vascular malformations were more common in patients with HHT2. Cerebral arteriovenous malformations were more common in patients with HHT1, but spinal arteriovenous malformations were seen only in patients with HHT2. Truncating mutations in ENG were associated with more affected organs and more severe hemorrhaging than were missense mutations. We conclude that HHT2 has a later onset than HHT1 and the former may disproportionately involve smaller vessels in tissues with more significant vascular remodeling.     

Novel mutations and polymorphisms in genes causing hereditary hemorrhagic telangiectasia

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant vascular disorder caused by mutations in Endoglin (ENG) or activin receptor-like kinase-1 (ALK1, ACVRL1) genes. We performed molecular characterization in clinically affected probands of 31 HHT families and detected a total of 28 different mutations in the two genes, including four shared by more than one family. Twelve mutations were identified in the ENG gene, six of which were novel and comprised two nonsense mutations in exons 6 and 8, deletions in exons 5 and 11, and splice site mutations in exon 12 and intron 8. Eleven of sixteen mutations identified in the ALK1 gene were novel single base pair substitutions in exons 4, 7, 8, and 9. We also describe the first de novo ALK1 mutation that causes a previously unreported c.1133C>A substitution of a highly conserved residue (p.P378H). The proband and his two daughters, who also carried the familial mutation, all suffered from gastrointestinal (GI) bleeding. In addition, we report seven newly identified polymorphisms and summarize all known ones in both genes.     

Quality of life in patients with hereditary hemorrhagic telangiectasia in Norway: a population based study

Hereditary hemorrhagic telangiectasia (HHT) is a rare, autosomal dominant disease characterized by the presence of recurrent epistaxis and small characteristic malformations of the peripheral blood vessels near the surface of the skin or mucosal linings. Arteriovenous malformations (AVM) of the lung, liver, and CNS are also known clinical findings. The purpose of this study was to examine quality of life (QoL) in patients with HHT in Norway. Sixty-six affected patients (39 women and 27 men) were included. QoL on overall-, health-related (HR-QoL), and disease-specific levels were measured with Cantril's Ladder (CL), Short Form 36 (SF-36), and a Symptom-specific QoL question in HHT patients (SFB-HHT-Q), respectively. Comparisons were made between patients and an age and gender adjusted normative sample from the Norwegian population (N = 990). Overall, the results reflected that several HHT disease-related variables were associated with reduced QoL on all three levels; overall QoL (CL), HR-QoL (SF36) as well as disease-specific QoL (SFB-HHT-Q), while demographic variables impacted HR-QoL in HHT patients. Compared to the normative sample, all subscales of SF36, but bodily pain, were significantly poorer in the HHT patients. HHT disease variables had the strongest association with QoL compared to demographic variables. The results substantiate that disease severity is associated with poorer QoL in this patients. Pain contributed independently to all levels of QoL.