12-25227342-T-G

Variant names:

• chr12-25227342-T-G
• rs121913240
• NM_004985.5:c.182A>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_004985.5(KRAS):​c.182A>C​(p.Gln61Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q61H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.0 (0 hom., cov: 32)
  • Failed GnomAD Quality Control
• Consequence: KRAS NM_004985.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.00

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a chain GTPase KRas (size 185) in uniprot entity RASK_HUMAN there are 29 pathogenic changes around while only 0 benign (100%) 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 chr12-25227341-T-A is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.878

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KRAS	NM_004985.5	c.182A>C	p.Gln61Pro	missense_variant	Exon 3 of 5	ENST00000311936.8	NP_004976.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KRAS	ENST00000311936.8	c.182A>C	p.Gln61Pro	missense_variant	Exon 3 of 5	1	NM_004985.5	ENSP00000308495.3

Frequencies

GnomAD3 genomes AF: 0.00 AC: 0 AN: 152176 Hom.: 0 Cov.: 32 FAILED QC

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 152176 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74356

Gnomad4 AFR AF: 0.00

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: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

RASopathy Uncertain:1

Jul 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 61 of the KRAS protein (p.Gln61Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with undergoing clinical exome sequencing (PMID: 27848944). ClinVar contains an entry for this variant (Variation ID: 375966). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt KRAS protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects KRAS function (PMID: 34117033, 35944066). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	.;D
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.88	D;D
MetaSVM	Pathogenic	0.91	D
MutationAssessor	Pathogenic	3.5	M;M
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-5.4	D;D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0030	D;D
Polyphen		0.99	D;B
Vest4		0.88
MutPred		0.66		Gain of catalytic residue at A59 (P = 0);Gain of catalytic residue at A59 (P = 0);
MVP		0.97
MPC		3.0
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.99
gMVP		0.98

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: rs121913240; hg19: chr12-25380276; COSMIC: COSV55508574; COSMIC: COSV55508574;