chr9-21974703-T-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1PM2PP3

The NM_000077.5(CDKN2A):c.125A>G(p.Asn42Ser) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,208 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N42K) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

CDKN2A
NM_000077.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.61

Publications

2 publications found

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 Gene-Disease associations (from GenCC):

melanoma, cutaneous malignant, susceptibility to, 2
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
melanoma-pancreatic cancer syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, ClinGen, Labcorp Genetics (formerly Invitae), Ambry Genetics
familial atypical multiple mole melanoma syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
melanoma and neural system tumor syndrome
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

CDKN2A links:

ENSG00000264545 (HGNC:):

ENSG00000264545 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

PM1

In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 43 uncertain in NM_000077.5

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.811

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CDKN2A	NM_000077.5 link	c.125A>G	p.Asn42Ser	missense_variant	Exon 1 of 3	ENST00000304494.10	NP_000068.1	P42771-1K7PML8
CDKN2A	NM_058195.4 link	c.194-3495A>G		intron_variant	Intron 1 of 2	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.125A>G	p.Asn42Ser	missense_variant	Exon 1 of 3	1	NM_000077.5	ENSP00000307101.5		P42771-1
CDKN2A	ENST00000579755.2 link	c.194-3495A>G		intron_variant	Intron 1 of 2	1	NM_058195.4	ENSP00000462950.1		Q8N726-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461208

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726920

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52856

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111920

Other (OTH)

AF:

0.00

AC:

AN:

60370

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

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

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

CDKN2A-related disorder

Uncertain:1

Jul 18, 2024

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The CDKN2A c.125A>G variant is predicted to result in the amino acid substitution p.Asn42Ser. To our knowledge, this variant has not been reported in the literature or in gnomAD, indicating this variant is rare. This variant is interpreted as a variant of uncertain significance by multiple submitters in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/406711/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Melanoma and neural system tumor syndrome;C1835044:Melanoma, cutaneous malignant, susceptibility to, 2;C1838547:Melanoma-pancreatic cancer syndrome

Uncertain:1

Sep 02, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Mar 25, 2022

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.N42S variant (also known as c.125A>G), located in coding exon 1 of the CDKN2A gene, results from an A to G substitution at nucleotide position 125. The asparagine at codon 42 is replaced by serine, an amino acid with highly similar properties. This amino acid position is 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. -

Familial melanoma

Uncertain:1

Nov 27, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 42 of the CDKN2A (p16INK4a) protein (p.Asn42Ser). This variant is not present in population databases (gnomAD no frequency). 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: 406711). 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 disruptive. 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

Benign

0.30

BayesDel_addAF

Uncertain

0.050

BayesDel_noAF

Benign

-0.17

CADD

Uncertain

(source)

DANN

Benign

0.97

DEOGEN2

Uncertain

0.47

T;T;.

Eigen

Benign

0.15

Eigen_PC

Benign

-0.021

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.85

D;D;D

M_CAP

Pathogenic

0.64

MetaRNN

Pathogenic

0.81

D;D;D

MetaSVM

Uncertain

-0.099

PhyloP100

4.6

PrimateAI

Uncertain

0.68

PROVEAN

Uncertain

-4.3

D;.;D

REVEL

Uncertain

0.41

Sift

Uncertain

0.0020

D;.;D

Sift4G

Benign

0.071

T;T;T

Polyphen

1.0

D;.;.

Vest4

0.60

MutPred

0.44

Gain of glycosylation at N42 (P = 0.0405);Gain of glycosylation at N42 (P = 0.0405);Gain of glycosylation at N42 (P = 0.0405);

MVP

0.93

MPC

1.1

ClinPred

0.99

GERP RS

3.7

PromoterAI

-0.016

Neutral

(source)

Varity_R

0.51

gMVP

0.73

Mutation Taster

=43/57

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over