Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_194454.3(KRIT1):c.1360_1363delTCTC(p.Ser454LysfsTer40) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,224 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.
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]
Verdict is Pathogenic. Variant got 12 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 7-92222869-TGAGA-T is Pathogenic according to our data. Variant chr7-92222869-TGAGA-T is described in ClinVar as [Pathogenic]. Clinvar id is 449497.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr7-92222869-TGAGA-T is described in Lovd as [Pathogenic].
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Identified in multiple unrelated patients with cerebral cavernous malformations referred for genetic testing at GeneDx and in published literature (Cave-Riant et al., 2002); Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at a significant frequency in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 12404106) -