12-25215471-A-T

Variant names:

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 2P and 9B. PVS1_ModerateBP6BS1BS2

The NM_033360.4(KRAS):c.540T>A(p.Cys180*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000208 in 1,611,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000085 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00022 ( 0 hom. )

Consequence

KRAS
NM_033360.4 stop_gained

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:5

Conservation

PhyloP100: 3.05

Variant links:

Genes affected

KRAS (HGNC:6407): (KRAS proto-oncogene, GTPase) This gene, a Kirsten ras oncogene homolog from the mammalian ras gene family, encodes a protein that is a member of the small GTPase superfamily. A single amino acid substitution is responsible for an activating mutation. The transforming protein that results is implicated in various malignancies, including lung adenocarcinoma, mucinous adenoma, ductal carcinoma of the pancreas and colorectal carcinoma. Alternative splicing leads to variants encoding two isoforms that differ in the C-terminal region. [provided by RefSeq, Jul 2008]

KRAS links:

LOC124902899 (HGNC:):

LOC124902899 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -7 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0526 CDS is truncated, and there are 0 pathogenic variants in the truncated region.

BP6

Variant 12-25215471-A-T is Benign according to our data. Variant chr12-25215471-A-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46541.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Benign=1, Uncertain_significance=1}.

BS1

Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.0000854 (13/152198) while in subpopulation NFE AF= 0.000147 (10/68022). AF 95% confidence interval is 0.0000791. There are 0 homozygotes in gnomad4. There are 5 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

BS2

High AC in GnomAd4 at 13 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KRAS	NM_004985.5 link	c.451-5560T>A		intron_variant	Intron 4 of 4	ENST00000311936.8	NP_004976.2	P01116-2A0A024RAV5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KRAS	ENST00000311936.8 link	c.451-5560T>A		intron_variant	Intron 4 of 4	1	NM_004985.5	ENSP00000308495.3		P01116-2

Frequencies

GnomAD3 genomes

AF:

0.0000854

AC:

AN:

152198

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000756

AC:

AN:

251200

Hom.:

AF XY:

0.0000663

AC XY:

AN XY:

135770

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000199

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000150

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000221

AC:

323

AN:

1459674

Hom.:

Cov.:

AF XY:

0.000209

AC XY:

152

AN XY:

726350

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.000153

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000276

Gnomad4 OTH exome

AF:

0.000182

GnomAD4 genome

AF:

0.0000854

AC:

AN:

152198

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74362

show subpopulations

Gnomad4 AFR

AF:

0.0000724

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000201

Hom.:

Bravo

AF:

0.000117

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000577

AC:

EpiCase

AF:

0.000273

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:2

Jul 02, 2018

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: KRAS c.540T>A (p.Cys180X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay. However, gain-of-function is the established molecular mechanism for disease for KRAS variants associated with Noonan spectrum disorders. The variant allele was found at a frequency of 7.9e-05 in 276946 control chromosomes (gnomAD). The observed variant frequency is approximately 6-fold higher than the estimated maximal expected allele frequency for a pathogenic variant in KRAS causing Noonan Syndrome and Related Conditions phenotype (1.3e-05), strongly suggesting that the variant is benign. The variant, c.540T>A, has been reported in the literature in an individual presenting with obesity, webbed neck, acne, bilateral inguinal hernia repair, abnormal pubertal development (Bhoj_2016) and an individual presenting with constrictive pericarditis (Herkert_2018) in whom it was classified as "Likely Benign" and "VUS" respectively. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. A ClinVar submission from a clinical diagnostic laboratory (evaluation after 2014) cites the variant as uncertain significance. Another ClinVar submission from a clinical diagnostic laboratory (evaluation before 2014) indicate the variant co-occurred with another pathogenic variant in a different gene and the laboratory classified the variant as "likely benign." Based on the evidence outlined above, the variant was classified as benign. -

Nov 07, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Cys180X in exon 5 of KRAS: This variant is not expected to have clinical signifi cance because it has been previously identified by our laboratory in one individ ual who does not have clinical features of Noonan spectrum disorders and a secon d individual who is affected but carries a pathogenic variant in another gene wh ich is likely responsible for the disease. In addition, variants associated with Noonan spectrum disorders are typically gain-of-function; therefore, nonsense v ariants such as this are not common. Furthermore, this variant is located in an exon which is alternatively spliced in one isoform of KRAS. No pathogenic sequen ce variants in this region of the gene have been previously described. This vari ant has also been identified in 0.01% (1/8598) of European American chromosomes by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS; dbSNP r s373169526). In summary, this variant is likely benign. -

not provided

Benign:2

Oct 31, 2016

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 26122175, 29625052, 26689913) -

Aug 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

KRAS: BS2 -

Cardio-facio-cutaneous syndrome

Uncertain:1

Mar 29, 2021

St. Jude Molecular Pathology, St. Jude Children's Research Hospital

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The KRAS c.540T>A (p.Cys180X) change is a nonsense variant in an alternate transcript of the KRAS gene that is predicted to cause protein truncation. The disease mechanism for RASopathies is gain-of-function caused by missense changes and protein truncating variants do not have an established correlation to disease (BP1). This variant has a maximum subpopulation frequency of 0.015% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/variant/12-25368405-A-T?dataset=gnomad_r2_1). This is neither rare or greater than expected for the disorder based on thresholds defined by the ClinGen RASopathy Variant Curation Expert Panel (PMID:29493581). This variant has been reported in an individual with constrictive pericarditis (PMID: 29517769), as well as individuals who do not present with clinical features of RASopathy disorders (PMID: 27763634, internal data). Data deposited into ClinVar indicates that this variant was identified in an individual who is affected by carries a pathogenic variant in another gene which is likely responsible for the disease (ClinVar Accession: SCV000063500.5). In summary, this variant meets criteria to be classified as of uncertain significance based on the ACMG/AMP criteria, as specified by the ClinGen RASopathy Variant Curation Expert Panel: BP1. -

Cardiovascular phenotype

Benign:1

Jan 31, 2025

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.62

CADD

Benign

DANN

Uncertain

0.99

Eigen

Pathogenic

0.98

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Uncertain

0.94

Vest4

0.93

GERP RS

5.5

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.11

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over