chr7-92241099-AACTT-A

Variant names:

• chr7-92241099-AACTT-A
• rs886039400
• NM_194454.3:c.152_155delAAGT

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_194454.3(KRIT1):​c.152_155delAAGT​(p.Lys51IlefsTer13) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KRIT1 NM_194454.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 7.03
• Publications: 0 publications found

Genes affected

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

ENSG00000289027 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 18 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 7-92241099-AACTT-A is Pathogenic according to our data. Variant chr7-92241099-AACTT-A is described in ClinVar as [Pathogenic]. Clinvar id is 265214.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
KRIT1	NM_194454.3	c.152_155delAAGT	p.Lys51IlefsTer13	frameshift_variant	Exon 5 of 19	ENST00000394505.7	NP_919436.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KRIT1	ENST00000394505.7	c.152_155delAAGT	p.Lys51IlefsTer13	frameshift_variant	Exon 5 of 19	1	NM_194454.3	ENSP00000378013.2
ENSG00000289027	ENST00000692281.1	c.152_155delAAGT	p.Lys51IlefsTer13	frameshift_variant	Exon 5 of 26			ENSP00000510568.1
ENSG00000285953	ENST00000458493.6	c.152_155delAAGT	p.Lys51IlefsTer13	frameshift_variant	Exon 4 of 20	4		ENSP00000396352.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000206 AC: 3 AN: 1459438 Hom.: 0 AF XY: 0.00000275 AC XY: 2 AN XY: 726316

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33440

American (AMR) AF: 0.00 AC: 0 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26114

East Asian (EAS) AF: 0.00 AC: 0 AN: 39658

South Asian (SAS) AF: 0.00 AC: 0 AN: 86200

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1109818

Other (OTH) AF: 0.00 AC: 0 AN: 60326

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000034), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cerebral cavernous malformation Pathogenic:2

Nov 27, 2024

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 (p.Lys51Ilefs*13) in the KRIT1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in KRIT1 are known to be pathogenic (PMID: 10508515, 11222804, 12404106, 24689081). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with cerebral cavernous malformations (PMID: 11161805; internal data). ClinVar contains an entry for this variant (Variation ID: 265214). For these reasons, this variant has been classified as Pathogenic. -

-

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has been reported in the literature in at least 1 individual with cerebral cavernous malformation (Sahoo 2001 PMID:11161805). This variant is not present in large control databases. This variant is present in ClinVar, with several labs classifying this variant as pathogenic (Variation ID:265214). Evolutionary conservation and computational predictive tools for this variant are limited or unavailable. This variant is a deletion of 4 nucelotides at position 152 and creates a premature stop codon 13 amino acids downstream from this location which results in an absent or abnormal protein. Loss of function variants are a known mechanism of disease for this gene (Cianfruglia 2019 PMID:30658464). In summary, this variant is classified as pathogenic based on the data above. -

KRIT1-related disorder Pathogenic:1

Oct 30, 2023

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The KRIT1 c.152_155delAAGT variant is predicted to result in a frameshift and premature protein termination (p.Lys51Ilefs*13). This variant has been reported to be causative for cerebral cavernous malformations (CCMs) (Sahoo et al 2001. PubMed ID: 11161805). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Frameshift variants in KRIT1 are expected to be pathogenic. This variant is interpreted as pathogenic. -

Hereditary cavernous hemangioma of brain Pathogenic:1

Jun 06, 2023

Molecular Genetics, Royal Melbourne Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change in KRIT1 is a frameshift variant predicted to cause a premature stop codon, p.(Lys51Ilefs*13), in biologically relevant exon 5/19 leading to nonsense-mediated decay in a gene in which loss-of-function is an established mechanism of disease (PMID: 20301470). This variant is absent from the population database gnomAD v2.1 and v3.1.This variant has been reported in at least two individuals with KRIT1-related cerebral cavernous malformations (PMID: 11161805; ClinVar: SCV000948377.3). Based on the classification scheme RMH Modified ACMG/AMP Guidelines v1.6.1, this variant is classified as PATHOGENIC. Following criteria are met: PVS1, PM2_Supporting, PS4_Supporting -

not provided Pathogenic:1

Dec 20, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 11161805) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.0
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs886039400; hg19: chr7-91870413;