Genetic Variant KRAS:p.Ala146Thr (chr12-25225628-C-T) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PM5PP2PP3_ModeratePP5

The NM_004985.5(KRAS):c.436G>A(p.Ala146Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,612,834 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A146S) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

KRAS
NM_004985.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:5U:2O:3

Conservation

PhyloP100: 7.89

Publications

780 publications found

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 Gene-Disease associations (from GenCC):

cardiofaciocutaneous syndrome 2
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
Noonan syndrome
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
Noonan syndrome 3
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp, G2P
cardiofaciocutaneous syndrome
Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen
linear nevus sebaceous syndrome
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
Costello syndrome
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
Noonan syndrome with multiple lentigines
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
Noonan syndrome-like disorder with loose anagen hair
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

KRAS links:

ENSG00000275197 (HGNC:):

ENSG00000275197 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 ACMG points.

PM1

In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_004985.5

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr12-25225628-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 40461.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 65 curated pathogenic missense variants (we use a threshold of 10). The gene has 3 curated benign missense variants. Gene score misZ: 2.3177 (below the threshold of 3.09). Trascript score misZ: 3.0857 (below the threshold of 3.09). GenCC associations: The gene is linked to cardiofaciocutaneous syndrome, cardiofaciocutaneous syndrome 2, Noonan syndrome 3, Noonan syndrome, Costello syndrome, linear nevus sebaceous syndrome.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.913

PP5

Variant 12-25225628-C-T is Pathogenic according to our data. Variant chr12-25225628-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 197243.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004985.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KRAS	NM_033360.4	MANE Plus Clinical	c.436G>A	p.Ala146Thr	missense	Exon 4 of 6	NP_203524.1	P01116-1
KRAS	NM_004985.5	MANE Select	c.436G>A	p.Ala146Thr	missense	Exon 4 of 5	NP_004976.2
KRAS	NM_001369786.1		c.436G>A	p.Ala146Thr	missense	Exon 4 of 6	NP_001356715.1	P01116-1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
KRAS	ENST00000256078.10	TSL:1 MANE Plus Clinical	c.436G>A	p.Ala146Thr	missense	Exon 4 of 6	ENSP00000256078.5	P01116-1
KRAS	ENST00000311936.8	TSL:1 MANE Select	c.436G>A	p.Ala146Thr	missense	Exon 4 of 5	ENSP00000308495.3	P01116-2
KRAS	ENST00000685328.1		c.436G>A	p.Ala146Thr	missense	Exon 4 of 5	ENSP00000508921.1	P01116-2

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151982

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1460852

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726792

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33452

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26098

East Asian (EAS)

AF:

0.00

AC:

AN:

39554

South Asian (SAS)

AF:

0.00

AC:

AN:

86238

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53224

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5740

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111476

Other (OTH)

AF:

0.0000166

AC:

AN:

60354

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.250

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151982

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74218

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41410

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5204

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10570

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67936

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000433

Hom.:

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (2)

Cardiofaciocutaneous syndrome 2 (1)

Classic Hodgkin lymphoma (1)

OCULOECTODERMAL SYNDROME, SOMATIC (1)

RASopathy (1)

Vascular malformation (1)

Adenocarcinoma of the large intestine (1)

Encephalocraniocutaneous lipomatosis (1)

Germinoma (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.42

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.93

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.94

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.95

M_CAP

Pathogenic

0.33

MetaRNN

Pathogenic

0.91

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.3

PhyloP100

7.9

PrimateAI

Pathogenic

0.88

PROVEAN

Uncertain

-3.6

REVEL

Pathogenic

0.91

Sift

Uncertain

0.0090

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.86

MutPred

0.72

Gain of catalytic residue at R151 (P = 0.0012)

MVP

1.0

MPC

0.34

ClinPred

1.0

GERP RS

5.5

Varity_R

0.94

gMVP

0.85

Mutation Taster

=4/96

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over