Analysis of ENG and ACVRL1 genes in 137 HHT Italian families identifies 76 different mutations (24 novel). Comparison with other European studies

Abstract

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder causing vascular dysplasias. About 70-80% of HHT patients carries mutations in ENG or ACVRL1 genes, which code for a TGFb receptor type III and I respectively. Molecular data on a large cohort of Italian HHT patients are presented, discussing the significance of missense and splice site mutations. Mutation analysis in ENG and ACVRL1 genes was performed using single strand conformation polymorphisms (SSCP), denaturing high performance liquid chromatography (DHPLC) and subsequent direct sequencing. Overall, 101 mutations were found, with ACVRL1 involved in 71% of cases. The highest number of mutations (28/101 subjects, 14/76 different mutations referring to both genes) was in ACVRL1, exon 3. Mutation analysis was then extended to a total of 356 family members, and 162 proven to carry the mutation. New polymorphisms were identified in both genes, and evidence that ENG P131L change is not a disease-causing mutation was also provided. An in silico analysis was performed in order to characterize splice-site mutations. These results were compared to other European national studies and data from Italy, France and Spain were consistent for an higher incidence of ACVRL1 mutations.

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

“…EdTA-anticoagulated blood samples from HHT patients were collected, and genomic dNA was extracted using standard procedures. Coding exons and exon-intron boundaries of ENG (Genbank NM_000118) and ACVRL1 (Genbank NM_000020) genes were amplified according to the procedure given by Olivieri et al 23 and sequenced. We also used the p093-B1 SAlSA MlpA kit HHT/ppH1 (MRC-Holland, Amsterdam, The Netherlands) to analyze large deletions or duplications in ACVRL1, ENG, and BMPR2 genes according to the manufacturer's instructions.…”

“…23 Five mutations are as yet unpublished (patients 2, 11, 15, 17, and 19 in Table 2), and one of these is a duplication of exons 5, 6, and 7 of ENG, analyzed by multiplex ligation-dependent probe amplification. Moreover, in two patients, the disease-causing mutation is still unknown.…”

Novel ACLV1 Mutation Identified in Late Onset Hereditary Hemorrhagic Telangiectasia

“…The Smad dimer then enters the nucleus where it acts as a transcription factor, regulating the transcription of angiogenesis genes such as VEGF. Reduced presence of endoglin, a coreceptor for ALK family of receptors, has been shown to decrease the activity of the ALK1 pathway, as well as the ALK5 pathway that counterbalances ALK1 activity by promoting cell c.24A > T Missense p.Lys8Ans [16] c.31_50del20 Deletion p.Leu11Glyfs*20 [17] c.37delC Deletion p.Leu13Cysfs*2 [18] c.50dupT Duplication p.Leu17Phefs*21 [19] c.50_53delTGGT Deletion p.Leu*17 [20] c.61 + 1G > A Missense p.? [14] c.61 + 10G > A Splice Site p.?…”

“…[30] c.526-1G > A Missense p.? [14] c.526G > T Missense p.Asp176Tyr [37] c.526delG Deletion p.Asp176Thrfs*82 [19] c.536A > C Missense p.Asp179Ala [51] c.540_541insA Insertion p.Asp181Argfs*44 [29] c.563delC Deletion p.Ser188* [19] c.567delG Deletion p.Leu190Serfs*68 [47] c.573delC Deletion p.Phe192Serfs*66 [26] c.590C > T Missense p.Thr197Ile [24] c.593T > A Missense p.Val198Glu [52] c.598C > G Missense p.Arg200Gly [43] c.601C > T Missense p.Gln201* [45] c.601C > A Missense p.Gln201Lys [30] c.602A > G Missense p.Gln201Arg [53] c.602A > C Missense p.Gln201Pro [19] c.611T > G Missense p.Leu204Trp [19] c.614T > G Missense p.Val205Gly [43] c.617A > G Missense p.Glu206Gly [20] c.617_625delAGTGTGTGG Deletion p.Glu206_Val208del [54] c.620delG Deletion p.Cys207Leufs*51 [14] c.623_624dupTG Duplication p.Gly209Trpfs*50 [39] c.626-9_629del13 Deletion p.? [37] c.626-5_634del14 Deletion p.?…”

“…[39] c.626-3C > G Splice Site p.? [55] c.632G > A Missense p.Gly211Asp [51] c.639T > G Missense p.Tyr213* [14] c.641delG Deletion p.Gly214Alafs*44 [45] c.643G > A Missense p.Glu215Lys [31] c.647T > G Missense p.Val216Gly [19] c.649T > G Missense p.Trp217Gly [45] c.650G > A Missense p.Trp217* [20] c.651G > A Missense p.Trp217* [24] c.653_654delGGinsCC Delins p.Arg218Pro [52] c.656G > A Missense p.Gly219Asp [24] c.661T > G Missense p.Trp221Gly [14] c.662G > A Missense p.Trp221* [19] c.663G > A Missense p.Trp221* [47] c.664_668delCACGG Deletion p.His222* [31] Continued c.667G > C Missense p.Gly223Arg [31] c.670G > A Missense p.Glu224Lys [25] c.673A > T Missense p.Ser225Cys [16] c.673_674delAG Deletion p.Ser225Cysfs*11 [47] c.676G > C Missense p.Val226Leu [30] c.677T > A Missense p.Val226Glu [45] c.682delG Deletion p.Val228Serfs*30 [31] c.683T > A Missense p.Val228Asp [19] c.686A > T Missense p.Lys229Met [55] c.686A > G Missense p.Lys229Arg [31] c.696_698delCTC Deletion p.Ser233del [56] c.698C > T Missense p.Ser233Leu [37] c.698C > A Missense p.Ser233* [57] c.704delA Deletion p.Asp235Valfs*23 [31] c.709C > T Missense p.Gln237* [25] c.716G > A Missense p.Trp239* [46] c.743_744delCA Deletion p.Thr248Serfs*143 [29] c.760_762delGAC Deletion p.Asp254del [18] c.759_761delCGA Deletion p.Asp254del [31] c.772 + 3_772 + 4dupAA Duplication p.? [43] c.772 + 5G > A Missense p.?…”