7-45000364-G-A

Variant names:

• chr7-45000364-G-A
• rs1562848479
• NM_031443.4:c.30+1G>A

Variant summary

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

The NM_031443.4(CCM2):​c.30+1G>A variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 24)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CCM2 NM_031443.4 splice_donor, intron
• Scores: Splicing: ADA: 0.00007757
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 1.58

Genes affected

CCM2 (HGNC:21708): (CCM2 scaffold protein) This gene encodes a scaffold protein that functions in the stress-activated p38 Mitogen-activated protein kinase (MAPK) signaling cascade. The protein interacts with SMAD specific E3 ubiquitin protein ligase 1 (also known as SMURF1) via a phosphotyrosine binding domain to promote RhoA degradation. The protein is required for normal cytoskeletal structure, cell-cell interactions, and lumen formation in endothelial cells. Mutations in this gene result in cerebral cavernous malformations. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Nov 2009]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-45000364-G-A is Pathogenic according to our data. Variant chr7-45000364-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 590655.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
CCM2	NM_031443.4	c.30+1G>A		splice_donor_variant, intron_variant	Intron 1 of 9	ENST00000258781.11	NP_113631.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CCM2	ENST00000258781.11	c.30+1G>A		splice_donor_variant, intron_variant	Intron 1 of 9	1	NM_031443.4	ENSP00000258781.7

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1156554 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 558626

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: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 24

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Feb 15, 2020

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 19, 2021

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is expected to severely impact normal RNA splicing, and consequently, protein structure and/or function. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). This variant has been identified in at least one individual with clinical features associated with this gene. -

Apr 01, 2025

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 19088124, 15122722, 14624391, 17160895, 34426522, 18300272) -

Cerebral cavernous malformation 2 Pathogenic:2

Dec 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 1 of the CCM2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CCM2 are known to be pathogenic (PMID: 18300272, 24689081). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with cerebral cavernous malformations (PMID: 15122722, 19088124). This variant is also known as IVS+1G>A. ClinVar contains an entry for this variant (Variation ID: 590655). Algorithms developed to predict the effect of variants on gene product structure and function are not available or were not evaluated for this variant. Experimental studies have shown that disruption of this splice site affects CCM2 function (PMID: 19088124). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Aug 21, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CCM2 c.30+1G>A variant (rs1562848479, ClinVar Variation ID: 590655) is reported in the literature in individuals affected with cerebral cavernous malformations (Stahl 2008, Verlaan 2004). This variant is absent from the Genome Aggregation Database (v2.1.1), indicating it is not a common polymorphism. This variant disrupts the canonical splice donor site of intron 1, which is likely to negatively impact gene function. In vitro functional analysis by immunohistochemistry shows localized loss of CCM2 expression in the cavernous endothelial cells (Pagenstecher 2009). Based on available information, this variant is considered to be pathogenic. References: Pagenstecher A et al. A two-hit mechanism causes cerebral cavernous malformations: complete inactivation of CCM1, CCM2 or CCM3 in affected endothelial cells. Hum Mol Genet. 2009 Mar 1;18(5):911-8. PMID: 19088124. Stahl S et al. Novel CCM1, CCM2, and CCM3 mutations in patients with cerebral cavernous malformations: in-frame deletion in CCM2 prevents formation of a CCM1/CCM2/CCM3 protein complex. Hum Mutat. 2008 May;29(5):709-17. PMID: 18300272. Verlaan DJ et al. CCM2 mutations account for 13% of cases in a large collection of kindreds with hereditary cavernous malformations. Ann Neurol. 2004 May;55(5):757-8. PMID: 15122722. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Benign	-0.68
CADD	Pathogenic	26
DANN	Benign	0.91
Eigen	Uncertain	0.37
Eigen_PC	Benign	-0.0049
FATHMM_MKL	Benign	0.11	N
GERP RS		1.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000078
dbscSNV1_RF	Benign	0.010
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.46		Position offset: 31
DS_DL_spliceai		0.99		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1562848479; hg19: chr7-45039963;