rs1555152774

Positions:

• chr12-51913988-T-TA

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000020.3(ACVRL1):​c.540_541insA​(p.Asp181fs) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: ACVRL1 NM_000020.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 1.10

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-51913988-T-TA is Pathogenic according to our data. Variant chr12-51913988-T-TA is described in ClinVar as [Pathogenic]. Clinvar id is 464763.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.540_541insA	p.Asp181fs	frameshift_variant	5/10	ENST00000388922.9	NP_000011.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ACVRL1	ENST00000388922.9	c.540_541insA	p.Asp181fs	frameshift_variant	5/10	1	NM_000020.3	ENSP00000373574.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Mar 27, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Aug 19, 2024	PM2, PS4_moderate, PVS1 -

ACVRL1-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

May 01, 2024

The ACVRL1 c.540_541insA variant is predicted to result in a frameshift and premature protein termination (p.Asp181Argfs*44). This variant has been reported in individuals with hereditary haemorrhagic telangiectasia (Wehner et al 2006. PubMed ID: 16542389; McDonald J et al 2020. PubMed ID: 32300199; Sadick H et al 2009. PubMed ID: 19508727). This variant has not been reported in a large population database, indicating this variant is rare. Frameshift variants in ACVRL1 are expected to be pathogenic. This variant is interpreted as pathogenic. -

Telangiectasia, hereditary hemorrhagic, type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 17, 2023

For these reasons, this variant has been classified as Pathogenic. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Asp181Argfs*44) in the ACVRL1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in ACVRL1 are known to be pathogenic (PMID: 15879500). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 464763). This variant is also known as p.D181fs. This premature translational stop signal has been observed in individuals with hereditary hemorrhagic telangiectasia (PMID: 16542389, 19508727, 21158752; Invitae). -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 10, 2021

The c.540_541insA pathogenic mutation, located in coding exon 4 of the ACVRL1 gene, results from an insertion of one nucleotide at position 540, causing a translational frameshift with a predicted alternate stop codon (p.D181Rfs*44). This mutation was identified in multiple German individuals, including three individuals from one family with epistaxis and telangiectasias (Wehner LE et al. Clin. Genet., 2006 Mar;69:239-45; Sadick H et al. BMC Med. Genet., 2009 Jun;10:53). This mutation was also reported in one individual from an hereditary hemorrhagic telangiectasia (HHT) genetic testing cohort (McDonald J et al. Clin Genet, 2011 Apr;79:335-44). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.25		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.25		Position offset: -14

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555152774; hg19: chr12-52307772;