rs771877309

Variant names:

• chr12-51915421-A-C
• rs771877309
• NM_000020.3:c.969A>C

Your query was ambiguous. Multiple possible variants found:

• chr12-51915421-A-C
• chr12-51915421-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP2

The NM_000020.3(ACVRL1):​c.969A>C​(p.Lys323Asn) variant causes a missense 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K323E) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000040 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: ACVRL1 NM_000020.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.167

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 uncertain in NM_000020.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-51915419-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1767756.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the ACVRL1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 203 curated pathogenic missense variants (we use a threshold of 10). The gene has 24 curated benign missense variants. Gene score misZ: 2.4458 (below the threshold of 3.09). Trascript score misZ: 3.182 (above the threshold of 3.09). GenCC associations: The gene is linked to hereditary hemorrhagic telangiectasia, telangiectasia, hereditary hemorrhagic, type 2.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ACVRL1	NM_000020.3	c.969A>C	p.Lys323Asn	missense_variant	Exon 7 of 10	ENST00000388922.9	NP_000011.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ACVRL1	ENST00000388922.9	c.969A>C	p.Lys323Asn	missense_variant	Exon 7 of 10	1	NM_000020.3	ENSP00000373574.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.0000397 AC: 58 AN: 1460694 Hom.: 0 Cov.: 32 AF XY: 0.0000482 AC XY: 35 AN XY: 726698

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.000857

Gnomad4 NFE exome AF: 0.00000719

Gnomad4 OTH exome AF: 0.0000829

GnomAD4 genome Cov.: 33

ExAC AF: 0.000824 AC: 100

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Telangiectasia, hereditary hemorrhagic, type 2 Uncertain:1

Apr 25, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces lysine with asparagine at codon 323 of the ACVRL1 protein (p.Lys323Asn). The lysine residue is highly conserved and there is a moderate physicochemical difference between lysine and asparagine. The frequency data for this variant (rs771877309) in the population databases is unreliable, as metrics indicate poor quality at this position in the ExAC database. This variant has not been reported in the literature in individuals with a ACVRL1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies. In summary, this variant is a rare missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D;.;T
Eigen	Benign	-0.10
Eigen_PC	Benign	-0.31
FATHMM_MKL	Benign	0.51	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Uncertain	0.68	D;D;D
MetaSVM	Uncertain	0.67	D
MutationAssessor	Benign	1.9	L;.;.
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-5.0	D;D;D
REVEL	Pathogenic	0.65
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.72
MutPred		0.79		Loss of methylation at K323 (P = 0.0204);.;.;
MVP		0.95
MPC		1.7
ClinPred		0.12	T
GERP RS		-6.3
Varity_R		0.99
gMVP		0.91

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs771877309; hg19: chr12-52309205;