rs1064794217

Variant names:

• chr12-51919074-C-T
• rs1064794217
• NM_000020.3:c.1336C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000020.3(ACVRL1):​c.1336C>T​(p.Gln446*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: ACVRL1 NM_000020.3 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.91
• Publications: 4 publications found

Genes affected

ACVRL1 (HGNC:175): (activin A receptor like type 1) This gene encodes a type I cell-surface receptor for the TGF-beta superfamily of ligands. It shares with other type I receptors a high degree of similarity in serine-threonine kinase subdomains, a glycine- and serine-rich region (called the GS domain) preceding the kinase domain, and a short C-terminal tail. The encoded protein, sometimes termed ALK1, shares similar domain structures with other closely related ALK or activin receptor-like kinase proteins that form a subfamily of receptor serine/threonine kinases. Mutations in this gene are associated with hemorrhagic telangiectasia type 2, also known as Rendu-Osler-Weber syndrome 2. [provided by RefSeq, Jul 2008]

ACVRL1 Gene-Disease associations (from GenCC):

• telangiectasia, hereditary hemorrhagic, type 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), ClinGen, Genomics England PanelApp
• hereditary hemorrhagic telangiectasia

  Inheritance: AR, AD Classification: SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 58 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-51919074-C-T is Pathogenic according to our data. Variant chr12-51919074-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 419979.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACVRL1	NM_000020.3	c.1336C>T	p.Gln446*	stop_gained	Exon 9 of 10	ENST00000388922.9	NP_000011.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACVRL1	ENST00000388922.9	c.1336C>T	p.Gln446*	stop_gained	Exon 9 of 10	1	NM_000020.3	ENSP00000373574.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Telangiectasia, hereditary hemorrhagic, type 2 Pathogenic:1

Jun 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln446*) in the ACVRL1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 58 amino acid(s) of the ACVRL1 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with hemorrhagic telangiectasia (PMID: 21158752). ClinVar contains an entry for this variant (Variation ID: 419979). This variant disrupts a region of the ACVRL1 protein in which other variant(s) (p.Arg479*) have been determined to be pathogenic (PMID: 15024723, 15065824, 15517393, 15712271, 16429404, 16540754, 18673552, 21158752, 23722869). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Mar 21, 2017

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Q446X variant in the ACVRL1 gene has been reported in one individual with HHT (McDonald et al., 2011). The Q446X variant is predicted to cause loss of normal protein function by protein truncation, as the last 58 amino acid residues of the protein are lost. Other nonsense variants in the ACVRL1 gene, including several downstream, have been reported in Human Gene Mutation Database in association with HHT (Stenson et al., 2014). Furthermore, the Q446X variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). Nevertheless, this variant lacks a sufficient number of probands, segregation data, and functional studies to be able to definitively determine is pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	43
DANN	Uncertain	1.0
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		7.9
Vest4		0.97
GERP RS		5.0
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1064794217; hg19: chr12-52312858;