rs774330517

chr7-92236447-T-C

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP4

The NM_194454.3(KRIT1):c.451A>G(p.Thr151Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000413 in 1,454,476 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: KRIT1 NM_194454.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 2.39

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]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.2705971).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KRIT1	NM_194454.3	c.451A>G	p.Thr151Ala	missense_variant	7/19	ENST00000394505.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KRIT1	ENST00000394505.7	c.451A>G	p.Thr151Ala	missense_variant	7/19	1	NM_194454.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251118 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135760

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000413 AC: 6 AN: 1454476 Hom.: 0 Cov.: 27 AF XY: 0.00000691 AC XY: 5 AN XY: 724074

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000253

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000665

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000189

ExAC AF: 0.00000824 AC: 1

Asia WGS AF: 0.00173 AC: 6 AN: 3474

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cerebral cavernous malformation Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	May 15, 2020	This sequence change replaces threonine with alanine at codon 151 of the KRIT1 protein (p.Thr151Ala). The threonine residue is moderately conserved and there is a small physicochemical difference between threonine and alanine. This variant is present in population databases (rs774330517, ExAC 0.009%). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The alanine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with KRIT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 468216). -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Angiokeratoma corporis diffusum with arteriovenous fistulas Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.078
BayesDel_addAF	Benign	-0.035	T
BayesDel_noAF	Benign	-0.21
Cadd	Benign	17
Dann	Uncertain	0.98
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.14
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Benign	0.67	T;T;.;.;.;T;T;T;T
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.27	T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.51	T
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Benign	0.42	T
Polyphen		0.14	.;B;B;B;B;.;.;.;.
Vest4		0.28, 0.27, 0.30, 0.28, 0.26
MutPred		0.70		Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);Loss of phosphorylation at T147 (P = 0.1376);
MVP		0.84
MPC		0.28
ClinPred		0.12	T
GERP RS		2.8
Varity_R		0.14
gMVP		0.33

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs774330517; hg19: chr7-91865761;