chr9-21974821-G-A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2BP4_ModerateBP6

The NM_000077.5(CDKN2A):c.7C>T(p.Pro3Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000188 in 1,591,586 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign 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. P3L) has been classified as Likely benign.

Frequency

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

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

CDKN2A
NM_000077.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:1

Conservation

PhyloP100: 0.0240

Publications

7 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: Likely_benign. The variant received -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.07120243).

BP6

Variant 9-21974821-G-A is Benign according to our data. Variant chr9-21974821-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 532281.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000077.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CDKN2A	NM_000077.5	MANE Select	c.7C>T	p.Pro3Ser	missense	Exon 1 of 3	NP_000068.1
CDKN2A	NM_058195.4	MANE Plus Clinical	c.194-3613C>T		intron	N/A	NP_478102.2
CDKN2A	NM_001195132.2		c.7C>T	p.Pro3Ser	missense	Exon 1 of 4	NP_001182061.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CDKN2A	ENST00000304494.10	TSL:1 MANE Select	c.7C>T	p.Pro3Ser	missense	Exon 1 of 3	ENSP00000307101.5
CDKN2A	ENST00000498124.1	TSL:1	c.7C>T	p.Pro3Ser	missense	Exon 1 of 4	ENSP00000418915.1
CDKN2A	ENST00000380151.3	TSL:1	n.7C>T		non_coding_transcript_exon	Exon 1 of 3	ENSP00000369496.3

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152076

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

GnomAD2 exomes

AF:

0.00000466

AC:

AN:

214480

AF XY:

0.00000840

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000602

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000139

AC:

AN:

1439510

Hom.:

Cov.:

AF XY:

0.00000140

AC XY:

AN XY:

715510

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:

32852

American (AMR)

AF:

0.00

AC:

AN:

42746

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25516

East Asian (EAS)

AF:

0.0000511

AC:

AN:

39170

South Asian (SAS)

AF:

0.00

AC:

AN:

85164

European-Finnish (FIN)

AF:

0.00

AC:

AN:

43816

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5160

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1105520

Other (OTH)

AF:

0.00

AC:

AN:

59566

⚠️ 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: 0.375

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:

152076

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74270

show subpopulations

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

African (AFR)

AF:

0.0000241

AC:

AN:

41428

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5160

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67988

Other (OTH)

AF:

0.00

AC:

AN:

2092

⚠️ 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: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Familial melanoma

Uncertain:1

Feb 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 3 of the CDKN2A (p16INK4a) protein (p.Pro3Ser). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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: 532281). 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.

Hereditary cancer-predisposing syndrome

Benign:1

Jun 18, 2024

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.072

BayesDel_addAF

Benign

-0.11

BayesDel_noAF

Benign

-0.40

CADD

Benign

(source)

DANN

Benign

0.89

DEOGEN2

Benign

0.068

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.0

FATHMM_MKL

Benign

0.050

LIST_S2

Benign

0.38

M_CAP

Benign

0.022

MetaRNN

Benign

0.071

MetaSVM

Benign

-0.99

PhyloP100

0.024

PrimateAI

Uncertain

0.61

PROVEAN

Benign

0.26

REVEL

Benign

0.072

Sift

Benign

0.13

Sift4G

Benign

0.62

Polyphen

0.0

Vest4

0.13

MutPred

0.33

Gain of phosphorylation at P3 (P = 0.0088)

MVP

0.65

MPC

0.39

ClinPred

0.034

GERP RS

1.3

PromoterAI

0.12

Neutral

(source)

Varity_R

0.049

gMVP

0.74

Mutation Taster

=11/89

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over