7-45000364-G-A

Variant summary

Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1 PM2 PP3_Strong PP5_Very_Strong

The NM_031443.4(CCM2):c.30+1G>A variant causes a splice donor 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
• Scores: Splicing: ADA: 0.00007757
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• 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 22 ACMG points.

• PVS1: Splicing 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
• PP3: BayesDel_addAF computational evidence supports a deleterious effect, 0.618
• 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/exons	MANE	UniProt
CCM2	NM_031443.4	c.30+1G>A		splice_donor_variant		ENST00000258781.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CCM2	ENST00000258781.11	c.30+1G>A		splice_donor_variant		1	NM_031443.4	P1

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:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Mar 19, 2021	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. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 13, 2023	Canonical splice site variant in a gene for which loss-of-function is a known mechanism of disease; Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 19088124, 15122722, 14624391, 17160895, 34426522, 18300272) -
Pathogenic, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	Feb 15, 2020	- -

Cerebral cavernous malformation 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Sep 19, 2023

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

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
MutationTaster	Benign	0.90	N;N;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;