Genotype-phenotype correlations in hereditary hemorrhagic teleangiectasia: data from the French-Italian-HHT network. Genet Med 9:14-22

University of Pavia, Ticinum, Lombardy, Italy
Genetics in Medicine (Impact Factor: 7.33). 02/2007; 9(1):14-22. DOI: 10.1097/GIM.0b013e31802d8373
Source: PubMed


Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by arteriovenous malformations (AVM), mostly cutaneous and mucous (telangiectases), but also involving the lungs (PAVM), liver (HAVM) and brain (CAVM). We studied the relationship between the phenotype and genotype in patients with a proven mutation in either ENG (HHT1) or ACVRL1 (HHT2).
Clinical features and their age of onset were compared between HHT1 and HHT2. The type of mutation was also analyzed. Clinical manifestations were distinguished from lesions found by screening.
Ninety-three HHT1 patients and 250 HHT2 patients were included. Epistaxis occurred later in HHT2, with incomplete penetrance (P<0.0001). Symptomatic PAVMs were more frequent in HHT1 (34.4 vs. 5.2%, P<0.001), as were cerebral abscesses (7.5 vs. 0.8%, P=0.002). Gastrointestinal bleeding occurred more frequently in HHT2 (16.4 vs. 6.5%, P=0.017). Symptomatic hepatic involvement was only seen in HHT2 patients. PAVMs were more frequently detected in asymptomatic HHT1 patients (54 vs. 12.8%, P<0.0001). PAVMs and HAVMs were often family clustered in HHT1 and HHT2, respectively. Truncating mutations were associated with a higher frequency of epistaxis and telangiectasis, in HHT2.
This study shows major differences between HHT1 and HHT2 phenotypes, which should be taken into account for future clinical studies.

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Available from: Cyril Goizet, Aug 19, 2014
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    • "The prevalence of hepatic VMs prevalence depends substantially on which genotype of HHT is present; genotype–phenotype correlation studies have demonstrated that hepatic VMs are significantly more frequent in patients who had the HHT2 genotype than in patients who had the HHT1 genotype [17–21]. Some studies have suggested that truncating mutations have a more dramatic effect on HHT phenotype than missense mutations have on HHT phenotype [22], with a greater frequency of nosebleeds, telangiectases and pulmonary VMs found in patients who have HHT with a truncating mutation [18]. "
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    ABSTRACT: 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. This prospective cohort study sought to assess the outcome of liver involvement in hereditary hemorrhagic telangiectasia patients. 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. 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%. This study shows that substantial morbidity and mortality are associated with liver vascular malformations in hereditary hemorrhagic telangiectasia patients.
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    • "Many studies report a mutation detection rate of up to 92% [27,28,33]. However, in our study we were able to identify only 43.9% of disease-causing mutations in a series of 41 HHT patients. "
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    ABSTRACT: Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, is an autosomal dominant disorder which is clinically characterised by recurrent epistaxis, mucocutaneous telangiectasia and visceral arteriovenous malformations. Genetic linkage studies identified two genes primarily related to HHT: endoglin (ENG) on chromosome 9q33-34 and activin receptor-like kinase1 (ACVRL1) on chromosome 12q13. We have screened a total of 41 unselected German patients with the suspected diagnosis of HHT. Mutation analysis for the ENG and ACVRL1 genes in all patients was performed by PCR amplification. Sequences were then compared to the HHT database sequences of the ENG mRNA (accession no. BC014271.2) and the ACVRL1 mRNA (accession no. NM000020.1). We identified 15 different mutations in 18 cases by direct sequencing. Among these mutations, one novel ENG mutation could be detected which has not yet been described in the literature before. The genotype-phenotype correlation was consistent with a higher frequency of pulmonary arteriovenous malformations in patients with ENG mutations than in patients with ACVRL1 mutations in our collective. For rapid genotyping of mutations and SNPs (single nucleotide polymorphisms) in ENG and ACVRL1, allele-specific PCR methods with sequence-specific primers (PCR-SSP) were established and their value analysed.
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    • "Moreover, the type and frequency of specific mutations in different localities can vary widely with some regions having a specific founder mutation. For example, a study in France and northern Italy revealed higher frequency (-2.7 times) of HHT-2 than HHT-1 (15). The prevalence of HHT in the Korean population appears to be low with only occasional cases being reported thus far. "
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    ABSTRACT: Hereditary hemorrhagic telangiectasia (HHT) is an inherited disorder that is characterized by abnormal communication between the arteries and veins in the skin, mucosa, and various organs. HHT has been reported to show significant phenotypic variability and genetic heterogeneity with wide ethnic and geographic variations. Although mutations in the endoglin (ENG) and activin A receptor type II-like 1 (ACVRL1) genes have been known to cause HHT for more than 10 yr, little is known about the clinical features or genetic background of Korean patients with HHT. In addition, mutations in mothers against decapentaplegic homolog 4 (SMAD4) are also seen in patients with the combined syndrome of juvenile polyposis and HHT. This study examined five Korean patients with the typical manifestations of HHT such as frequent epistaxis and pulmonary arteriovenous malformations. Direct sequencing of the ENG and ACVRL1 genes revealed one known mutation, ENG c.277C>T, in one patient and two novel mutations, ENG c.992-1G>C and ACVRL1 c.81dupT in two patients, respectively. The remaining two patients with negative results were screened for SMAD4 mutations as well as gross deletions of ENG and ACVRL1 using multiple ligation-dependent probe amplification, but none was detected. Despite the small number of patients investigated, we firstly report Korean patients with genetically confirmed HHT, and show the genetic and allelic heterogeneity underlying HHT.
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