rs1064794217

Positions:

• chr12-51919074-C-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong 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

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 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 7 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/exons	MANE	Protein	UniProt
ACVRL1	NM_000020.3	c.1336C>T	p.Gln446*	stop_gained	9/10	ENST00000388922.9	NP_000011.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ACVRL1	ENST00000388922.9	c.1336C>T	p.Gln446*	stop_gained	9/10	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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 09, 2017

This variant is not present in population databases (ExAC no frequency). For these reasons, this variant has been classified as Pathogenic. A different truncation downstream of this variant (p.Arg479*) has been determined to be pathogenic (PMID: 15024723, 15065824, 15517393, 15712271, 16429404, 16540754, 18673552, 21158752, 23722869). This suggests that deletion of this region of the ACVRL1 protein is causative of disease. This variant has been reported in an individual affected with hemorrhagic telangiectasia (PMID: 21158752). ClinVar contains an entry for this variant (Variation ID: 419979). This sequence change results in a premature translational stop signal in the ACVRL1 gene (p.Gln446*). While this is not anticipated to result in nonsense mediated decay, it is expected to delete the last 58 amino acids of the ACVRL1 protein. -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 21, 2017

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
Vest4		0.97
GERP RS		5.0

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

Publications

LitVar

Other links and lift over

dbSNP: rs1064794217; hg19: chr12-52312858;