NM_031443.4:c.42_43insATTTAAACGAGTATTTAAA

Variant names:

• chr7-45038264-C-CATTTAAACGAGTATTTAAA
• rs1554365511
• NM_031443.4:c.42_43insATTTAAACGAGTATTTAAA

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PP5_Moderate

The NM_031443.4(CCM2):​c.42_43insATTTAAACGAGTATTTAAA​(p.Ser15IlefsTer2) variant causes a frameshift, stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CCM2 NM_031443.4 frameshift, stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.56
• Publications: 0 publications found

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]

CCM2 Gene-Disease associations (from GenCC):

• cerebral cavernous malformation 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• famililal cerebral cavernous malformations

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 79 pathogenic variants in the truncated region.
• PP5: Variant 7-45038264-C-CATTTAAACGAGTATTTAAA is Pathogenic according to our data. Variant chr7-45038264-C-CATTTAAACGAGTATTTAAA is described in ClinVar as Pathogenic. ClinVar VariationId is 468336.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CCM2	NM_031443.4	c.42_43insATTTAAACGAGTATTTAAA	p.Ser15IlefsTer2	frameshift_variant, stop_gained	Exon 2 of 10	ENST00000258781.11	NP_113631.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CCM2	ENST00000258781.11	c.42_43insATTTAAACGAGTATTTAAA	p.Ser15IlefsTer2	frameshift_variant, stop_gained	Exon 2 of 10	1	NM_031443.4	ENSP00000258781.7

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cerebral cavernous malformation 2 Pathogenic:1

Aug 11, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal at codon 16 (p.Val14_Ser15insIle*) of the CCM2 gene. It is expected to result in an absent or disrupted protein product. While this particular variant has not been reported in the literature, loss-of-function variants in CCM2 are known to be pathogenic (PMID: 14624391). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.6
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs1554365511; hg19: chr7-45077863;