9-21974775-G-T

Position:

chr9-21974775-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_000077.5(CDKN2A):c.53C>A(p.Thr18Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 152,026 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Consequence

CDKN2A
NM_000077.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: -0.937

Variant links:

Genes affected

CDKN2A (HGNC:1787): (cyclin dependent kinase inhibitor 2A) This gene generates several transcript variants which differ in their first exons. At least three alternatively spliced variants encoding distinct proteins have been reported, two of which encode structurally related isoforms known to function as inhibitors of CDK4 kinase. The remaining transcript includes an alternate first exon located 20 Kb upstream of the remainder of the gene; this transcript contains an alternate open reading frame (ARF) that specifies a protein which is structurally unrelated to the products of the other variants. This ARF product functions as a stabilizer of the tumor suppressor protein p53 as it can interact with, and sequester, the E3 ubiquitin-protein ligase MDM2, a protein responsible for the degradation of p53. In spite of the structural and functional differences, the CDK inhibitor isoforms and the ARF product encoded by this gene, through the regulatory roles of CDK4 and p53 in cell cycle G1 progression, share a common functionality in cell cycle G1 control. This gene is frequently mutated or deleted in a wide variety of tumors, and is known to be an important tumor suppressor gene. [provided by RefSeq, Sep 2012]

CDKN2A links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM1

In a repeat ANK 1 (size 29) in uniprot entity CDN2A_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_000077.5

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.13468748).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CDKN2A	NM_000077.5 linkuse as main transcript	c.53C>A	p.Thr18Lys	missense_variant	1/3	ENST00000304494.10	NP_000068.1
CDKN2A	NM_058195.4 linkuse as main transcript	c.194-3567C>A		intron_variant		ENST00000579755.2	NP_478102.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CDKN2A	ENST00000304494.10 linkuse as main transcript	c.53C>A	p.Thr18Lys	missense_variant	1/3	1	NM_000077.5	ENSP00000307101	P2	P42771-1
CDKN2A	ENST00000579755.2 linkuse as main transcript	c.194-3567C>A		intron_variant		1	NM_058195.4	ENSP00000462950		Q8N726-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151910

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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

GnomAD3 exomes

AF:

0.00000433

AC:

AN:

230880

Hom.:

AF XY:

0.00

AC XY:

AN XY:

128072

show subpopulations

Gnomad AFR exome

AF:

0.0000753

Gnomad AMR exome

AF:

0.00

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

Cov.:

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152026

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74290

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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

ExAC

AF:

0.00000862

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Sep 02, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 16, 2022	The p.T18K variant (also known as c.53C>A), located in coding exon 1 of the CDKN2A gene, results from a C to A substitution at nucleotide position 53. The threonine at codon 18 is replaced by lysine, an amino acid with similar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Familial melanoma

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 07, 2023

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. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant¬†is likely to be tolerated. ClinVar contains an entry for this variant (Variation ID: 491580). This variant has not been reported in the literature in individuals affected with CDKN2A (p16INK4a)-related conditions. This variant is present in population databases (rs560518923, gnomAD 0.008%). This sequence change replaces threonine, which is neutral and polar, with lysine, which is basic and polar, at codon 18 of the CDKN2A (p16INK4a) protein (p.Thr18Lys). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.24

BayesDel_addAF

Benign

-0.16

BayesDel_noAF

Benign

-0.28

CADD

Benign

DANN

Benign

0.96

DEOGEN2

Benign

0.19

T;T;.

Eigen

Benign

-0.86

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.14

LIST_S2

Benign

0.69

T;T;T

M_CAP

Uncertain

0.26

MetaRNN

Benign

0.13

T;T;T

MetaSVM

Benign

-0.91

MutationTaster

Benign

1.0

N;N;N;N;N;N;N;N;N

PrimateAI

Uncertain

0.61

PROVEAN

Benign

-1.8

N;.;N

REVEL

Benign

0.19

Sift

Benign

0.24

T;.;T

Sift4G

Benign

0.92

T;T;T

Polyphen

0.85

P;.;.

Vest4

0.32

MutPred

0.35

Gain of ubiquitination at T18 (P = 0.0138);Gain of ubiquitination at T18 (P = 0.0138);Gain of ubiquitination at T18 (P = 0.0138);

MVP

0.94

MPC

0.53

ClinPred

0.13

GERP RS

-3.2

Varity_R

0.20

gMVP

0.88

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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