9-21971189-G-T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM1BP4BS1_SupportingBS2

The NM_000077.5(CDKN2A):c.170C>A(p.Ala57Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000689 in 1,597,598 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

CDKN2A
NM_000077.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 1.96

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:

ENSG00000264545 (HGNC:):

ENSG00000264545 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

PM1

In a repeat ANK 2 (size 28) in uniprot entity CDN2A_HUMAN there are 15 pathogenic changes around while only 3 benign (83%) in NM_000077.5

BP4

Computational evidence support a benign effect (MetaRNN=0.27536967).

BS1

Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.00000623 (9/1445364) while in subpopulation MID AF= 0.000698 (4/5730). AF 95% confidence interval is 0.000238. There are 0 homozygotes in gnomad4_exome. There are 4 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAdExome4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CDKN2A	NM_000077.5 link	c.170C>A	p.Ala57Asp	missense_variant	Exon 2 of 3	ENST00000304494.10	NP_000068.1	P42771-1K7PML8
CDKN2A	NM_058195.4 link	c.213C>A	p.Arg71Arg	synonymous_variant	Exon 2 of 3	ENST00000579755.2	NP_478102.2	Q8N726-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CDKN2A	ENST00000304494.10 link	c.170C>A	p.Ala57Asp	missense_variant	Exon 2 of 3	1	NM_000077.5	ENSP00000307101.5		P42771-1
CDKN2A	ENST00000579755.2 link	c.213C>A	p.Arg71Arg	synonymous_variant	Exon 2 of 3	1	NM_058195.4	ENSP00000462950.1		Q8N726-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152234

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00000908

AC:

AN:

220150

Hom.:

AF XY:

0.00000815

AC XY:

AN XY:

122640

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000295

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:

0.0000101

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000623

AC:

AN:

1445364

Hom.:

Cov.:

AF XY:

0.00000556

AC XY:

AN XY:

719474

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000225

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.0000333

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152234

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.0000654

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

Alfa

AF:

0.0000295

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000836

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:2

Aug 28, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CDKN2A locus encodes two different gene products, p16INK4a and p14ARF (https://www.ncbi.nlm.nih.gov/books/NBK7030/). This missense variant replaces alanine with aspartic acid at codon 57 of the CDKN2A (p16INK4A) protein. Computational prediction suggests that this variant may not impact protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with early-onset rectal cancer (PMID: 35029067) and in an individual unaffected with cancer (PMID: 29641532). This variant has been identified in 2/220150 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Jan 27, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A57D variant (also known as c.170C>A), located in coding exon 2 of the CDKN2A gene, results from a C to A substitution at nucleotide position 170. The alanine at codon 57 is replaced by aspartic acid, an amino acid with dissimilar properties. This alteration was identified in 1/1358 non-cancer control individuals and in 0/57 cases, in a study looking at cancer predisposition mutations in patients with cutaneous melanoma and a history of at least two additional non-cutaneous melanoma primary cancers (Pritchard AL et al. PLoS ONE, 2018 Apr;13:e0194098). This alteration has also been reported in a cohort of patients with Lynch syndrome-associated tumors and a personal or family history of sarcoma (de Angelis de Carvalho N et al. Cancers (Basel), 2020 Jul;12:). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Melanoma and neural system tumor syndrome

Uncertain:1

Feb 21, 2024

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Uncertain:1

Oct 18, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in an individual with endometrial sarcoma, tubular adenocarcinoma, and thyroid tumor (de Angelis de Carvalho et al., 2020); This variant is associated with the following publications: (PMID: 29641532, 32659967, 35029067) -

Melanoma, cutaneous malignant, susceptibility to, 2

Uncertain:1

Jul 02, 2018

Mendelics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Familial melanoma

Uncertain:1

Dec 29, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 57 of the CDKN2A (p16INK4a) protein (p.Ala57Asp). This variant is present in population databases (rs372266620, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with CDKN2A (p16INK4a)-related conditions. ClinVar contains an entry for this variant (Variation ID: 483325). 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. 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

Uncertain

0.44

BayesDel_addAF

Benign

-0.016

BayesDel_noAF

Benign

-0.18

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.21

T;T;.;.;.;.;T;.

Eigen

Benign

-0.58

Eigen_PC

Benign

-0.72

FATHMM_MKL

Benign

0.50

LIST_S2

Benign

0.83

T;T;.;T;.;T;T;T

M_CAP

Uncertain

0.17

MetaRNN

Benign

0.28

T;T;T;T;T;T;T;T

MetaSVM

Benign

-0.69

PrimateAI

Benign

0.37

PROVEAN

Benign

-2.2

N;.;.;N;.;.;.;.

REVEL

Uncertain

0.44

Sift

Benign

0.042

D;.;.;D;.;.;.;.

Sift4G

Benign

0.60

T;T;T;T;T;T;T;T

Polyphen

0.93

P;.;.;.;.;.;.;.

Vest4

0.36

MutPred

0.50

Loss of MoRF binding (P = 0.0448);Loss of MoRF binding (P = 0.0448);.;Loss of MoRF binding (P = 0.0448);.;.;.;.;

MVP

0.96

MPC

1.3

ClinPred

0.52

GERP RS

-1.0

Varity_R

0.48

gMVP

0.88

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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