Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2PP3_StrongPP5_Moderate
The ENST00000475770.6(KRIT1):n.959A>G variant causes a non coding transcript exon change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).
KRIT1 (HGNC:1573): (KRIT1 ankyrin repeat containing) This gene encodes a protein containing four ankyrin repeats, a band 4.1/ezrin/radixin/moesin (FERM) domain, and multiple NPXY sequences. The encoded protein is localized in the nucleus and cytoplasm. It binds to integrin cytoplasmic domain-associated protein-1 alpha (ICAP1alpha), and plays a critical role in beta1-integrin-mediated cell proliferation. It associates with junction proteins and RAS-related protein 1A (Rap1A), which requires the encoded protein for maintaining the integrity of endothelial junctions. It is also a microtubule-associated protein and may play a role in microtubule targeting. Mutations in this gene result in cerebral cavernous malformations. Multiple alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Sep 2009]
KRIT1 Gene-Disease associations (from GenCC):
cerebral cavernous malformation 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
famililal cerebral cavernous malformations
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Our verdict: Likely_pathogenic. The variant received 8 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
PP5
Variant 7-92234925-T-C is Pathogenic according to our data. Variant chr7-92234925-T-C is described in ClinVar as Pathogenic. ClinVar VariationId is 468218.Status of the report is criteria_provided_single_submitter, 1 stars.
For these reasons, this variant has been classified as Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in KRIT1 are known to be pathogenic (PMID: 10508515, 11222804, 12404106). This variant has been reported in individuals affected with cerebral cavernous malformations (PMID: 15079030, 23595507). It is also known as IVS8-2A>G in the literature. This variant is not present in population databases (ExAC no frequency). This sequence change affects an acceptor splice site in intron 9 of the KRIT1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -