Characterization of a family mutation in the 5’ untranslated region of the endoglin gene causative of hereditary hemorrhagic telangiectasia

Ruíz-Llorente, Lidia; McDonald, Jamie; Wooderchak-Donahue, Whitney; Briggs, Eric; Chesnutt, Mark S.; Bayrak-Toydemir, Pınar; Bernabeu, Carmelo

doi:10.1038/s10038-019-0564-x

Cited by 8 publications

(36 citation statements)

References 32 publications

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“…As a consequence, data accumulated in this work suggest classifying c.-79C>T and c.-68G>A variants also as likely pathogenic. Furthermore, our results obtained for ENG c.-142A>T that parallel those we observed for ENG c.-127C>T, classified as pathogenic in HHT database, and combined with published data 19 add strong support for this variant being pathogenic. The observed effects are concordant with those obtained by other groups [19][20][21] .…”

Section: Discussionsupporting

confidence: 89%

“…Two of these variants (c.-142A>T and c.-127C>T) have been analyzed in vitro in published studies and have been associated with a decrease of endoglin levels [19][20][21] . While c.-127C>T and c.-10C>T have been reported as pathogenic in public databases, the c.-142A>T is absent from databases but suggested to be pathogenic in Ruiz-Llorente et al, 2019 19 . An additional uAUG-creating variant (c.-9G>A) has been reported in the 5'UTR of ENG 20 .…”

Section: Introductionmentioning

confidence: 99%

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Novel uAUG creating variants in the 5’UTR of ENG causing Hereditary Hemorrhagic Telangiectasia

Soukarieh

Tillet

Proust

et al. 2022

Preprint

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Hereditary Hemorrhagic Telangiectasia (HHT) is a rare vascular disorder causing abnormal vessel formation and characterized by autosomal dominant transmission. The associated considerable variability in symptoms and clinical severity complicate the management of the disease. In clinical routine, 3 main genes, ACVRL1 (also known as ALK1), ENG and SMAD4 are screened for pathogenic variants at the origin of HHT. About 80% of HHT cases are caused by pathogenic coding variants in ACVRL1 and ENG. However, at least 15% remain with no molecular explanations in the 3 main genes. We here report the identification of 2 never reported variants, c.-79C>T and c.-68G>A, in the 5UTR of ENG in 2 unrelated HHT patients. These 2 variants are predicted to create upstream AUGs (uAUGs) in the 5UTR, which are in frame with a stop codon located within the CoDing Sequence (CDS), thus generating Overlapping upstream Open reading frames (uoORFs). In other cases, uAUGs can lead to fully upstream ORFs (uORFs) when associated with stop codons located within the 5UTR or to elongated CDS (eCDS) when in frame with the CDS and associated with the main stop codon. In order to assess the pathogenicity of these ENG variants, we performed in vitro functional assays based on the expression of wild-type and mutant constructs in human cells. We found that these 5UTR ENG variants were associated with a decrease of protein levels in HeLa and HUVEC cells. They were also associated with a decreased ability to activate BMP9-stimulated ALK1 receptor in a BMP-response element (BRE) assay. This assay is a mandatory element before providing a definitive molecular diagnosis and has been so far applied only on coding ENG variants. We applied the same experimental workflow on 3 additional uoORF-creating variants (c.-142A>T, c.-127C>T and c.-10C>T) and one eCDS-creating variant (c.-9G>A) in the 5UTR of ENG previously reported in HHT patients. We found that all the analysed uoORF-creating variants alter endoglin levels and function. A comparison of our experimental results with patients clinical characteristics suggests that uoORF-creating variants leading to ENG protein levels ≤ 40% in vitro would be associated with HHT. Additional experiments relying on an artificial deletion in our mutated constructs show that created uAUGs predicted to create uoORFs are able to initiate the translation indicating that the associated effect is likely caused by an alteration of the translation mechanism. Overall, we here identified two never reported 5UTR ENG variations in HHT patients and shed new lights on the role of upstream ORFs on ENG regulation. Our findings contribute to the amelioration of molecular diagnosis in HHT.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Novel uAUG creating variants in the 5’UTR of ENG causing Hereditary Hemorrhagic Telangiectasia

Soukarieh

Tillet

Proust

et al. 2022

Preprint

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“…ENG can be considered as a special gene with respect to upORFs. Indeed, four rare 5′UTR variants have been described so far in HHT patients to create uAUGs potentially at the origin of upORFs ( 18 , 34 – 37 , 77 ). These variants are NM_001114753.3: c.-142A>T, c.-127C>T, c.-10C>T, and c.-9G>A. Functional studies have been conducted for three of them (c.-142A>T, c.-127C>T, and c.-9G>A), bringing out an effect of the analyzed variants on the protein levels in vitro ( 18 , 35 – 37 , 77 ).…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, four rare 5′UTR variants have been described so far in HHT patients to create uAUGs potentially at the origin of upORFs ( 18 , 34 – 37 , 77 ). These variants are NM_001114753.3: c.-142A>T, c.-127C>T, c.-10C>T, and c.-9G>A. Functional studies have been conducted for three of them (c.-142A>T, c.-127C>T, and c.-9G>A), bringing out an effect of the analyzed variants on the protein levels in vitro ( 18 , 35 – 37 , 77 ). Interestingly, a moderate decrease (∼20%) of the protein levels has been associated with c.-9G>A variant compared to a drastic reduction observed for c.-142A>T and c.-127C>T (∼60% and ∼75%, respectively).…”

Section: Resultsmentioning

confidence: 99%

Common and Rare 5′UTR Variants Altering Upstream Open Reading Frames in Cardiovascular Genomics

Soukarieh

Meguerditchian

Proust

et al. 2022

Front. Cardiovasc. Med.

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High-throughput sequencing (HTS) technologies are revolutionizing the research and molecular diagnosis landscape by allowing the exploration of millions of nucleotide sequences at an unprecedented scale. These technologies are of particular interest in the identification of genetic variations contributing to the risk of rare (Mendelian) and common (multifactorial) human diseases. So far, they have led to numerous successes in identifying rare disease-causing mutations in coding regions, but few in non-coding regions that include introns, untranslated (UTR), and intergenic regions. One class of neglected non-coding variations is that of 5′UTR variants that alter upstream open reading frames (upORFs) of the coding sequence (CDS) of a natural protein coding transcript. Following a brief summary of the molecular bases of the origin and functions of upORFs, we will first review known 5′UTR variations altering upORFs and causing rare cardiovascular disorders (CVDs). We will then investigate whether upORF-affecting single nucleotide polymorphisms could be good candidates for explaining association signals detected in the context of genome-wide association studies for common complex CVDs.

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“…Heterozygous mutations in the endoglin gene ( ENG ) cause hereditary hemorrhagic telangiectasia (HHT). The pathogenic mutation c.‐142A>T in the 5′UTR of ENG has been reported to create an aberrant TIS and to affect the translation efficiency, resulting in HHT (Ruiz‐Llorente et al, ). The aberrant TIS made a longer alternative reading frame than the wild‐type reading frame, and the sequence around the aberrant TIS fits better with the Kozak consensus sequence than that around the original TIS.…”

Section: Discussionmentioning

confidence: 99%

Pathogenesis of a variant in the 5′ untranslated region of ADAR1 in dyschromatosis symmetrica hereditaria

Suganuma

Kono

Yamanaka³

et al. 2020

Pigment Cell Melanoma Res

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Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis caused by mutations in ADAR1. In this study, we performed mutation analysis on a family that included typical DSH patients. No mutations were found in any coding regions or exon–intron boundary regions of ADAR1, but a previously unreported non‐coding heterozygous variant, c.‐60A>G, was found in the 5′ untranslated region (5′UTR) of ADAR1 in the proband and her mother. The function of 5′UTR in mRNA is not well‐understood. To understand the pathogenesis of the variant and the function of the 5′UTR of ADAR1, we constructed two reporter genes carrying the ADAR1 5′UTR sequence with/without the variant between the PGK promoter and a luciferase coding sequence, and performed luciferase assays, semi‐quantitative PCR analyses, and polysomal assays. In human melanocytes, c.‐60A>G induced a 16% reduction in transcription and a 51% reduction in translation. Our results indicate that the 5′UTR c.‐60A>G variant adversely affects the post‐transcriptional step in gene expression, leading to DSH. Detailed functional assays of the 5′UTR of ADAR1 in the present study revealed the gene expression to be not only downregulated, but also upregulated by defects in 5′UTR depending on the locations. The regulation of translation by 5′UTR is very complicated.

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Characterization of a family mutation in the 5’ untranslated region of the endoglin gene causative of hereditary hemorrhagic telangiectasia

Cited by 8 publications

References 32 publications

Novel uAUG creating variants in the 5’UTR of ENG causing Hereditary Hemorrhagic Telangiectasia

Novel uAUG creating variants in the 5’UTR of ENG causing Hereditary Hemorrhagic Telangiectasia

Common and Rare 5′UTR Variants Altering Upstream Open Reading Frames in Cardiovascular Genomics

Pathogenesis of a variant in the 5′ untranslated region of ADAR1 in dyschromatosis symmetrica hereditaria

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