rs760065045

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 6P and 1B. PM1PM2PM5BP4

The NM_000077.5(CDKN2A):​c.58G>T​(p.Ala20Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,455,404 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign 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. A20P) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

CDKN2A
NM_000077.5 missense

Scores

1
4
13

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 3.47

Publications

18 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

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 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 44 uncertain in NM_000077.5
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr9-21974770-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 576362.
BP4
Computational evidence support a benign effect (MetaRNN=0.33109498).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CDKN2ANM_000077.5 linkc.58G>T p.Ala20Ser missense_variant Exon 1 of 3 ENST00000304494.10 NP_000068.1
CDKN2ANM_058195.4 linkc.194-3562G>T intron_variant Intron 1 of 2 ENST00000579755.2 NP_478102.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CDKN2AENST00000304494.10 linkc.58G>T p.Ala20Ser missense_variant Exon 1 of 3 1 NM_000077.5 ENSP00000307101.5
CDKN2AENST00000579755.2 linkc.194-3562G>T intron_variant Intron 1 of 2 1 NM_058195.4 ENSP00000462950.1

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD2 exomes
AF:
0.00000432
AC:
1
AN:
231482
AF XY:
0.00000779
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000972
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1455404
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
724276
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33446
American (AMR)
AF:
0.00
AC:
0
AN:
44650
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26052
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39682
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86160
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
48456
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5762
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1111044
Other (OTH)
AF:
0.00
AC:
0
AN:
60152
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000378
ExAC
AF:
0.00000858
AC:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2
May 02, 2025
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.A20S variant (also known as c.58G>T), located in coding exon 1 of the CDKN2A gene, results from a G to T substitution at nucleotide position 58. The alanine at codon 20 is replaced by serine, an amino acid with similar properties. In a cell cycle activity assay, this alteration showed normal binding to CDK4 and CDK6 proteins; however, authors noted that normal binding to CDK4 or CDK6 is a poor predictor of cell cycle function and pathogenicity and a normal result in the assay does not change the odds that a variant is pathogenic or neutral (Miller PJ et al. Hum Mutat. 2011; 32:900-11). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

Mar 09, 2023
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 serine at codon 20 of the CDKN2A (p16INK4A) protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Functional studies have shown that this variant does not impact binding to CDK4 and CDK6 in a cell cycle activity assay (PMID: 21462282). This variant has not been reported in individuals affected with CDKN2A-related disorders in the literature. This variant has been identified in 1/231482 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. -

Melanoma and neural system tumor syndrome Uncertain:1
Mar 27, 2024
Baylor Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
Apr 04, 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; A published functional study demonstrates normal binding of CDK4 and CDK6, similar to wildtype; however, the authors acknowledge that normal binding of CDK4 or CDK6 is a poor predictor of cell cycle function and pathogenicity (Miller et al., 2011); This variant is associated with the following publications: (PMID: 8834170, 7796400, 9132280, 21462282) -

Familial melanoma Uncertain:1
Sep 10, 2024
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 serine, which is neutral and polar, at codon 20 of the CDKN2A (p16INK4a) protein (p.Ala20Ser). This variant is present in population databases (rs760065045, gnomAD 0.001%). 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: 664488). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Experimental studies have shown that this missense change does not substantially affect CDKN2A (p16INK4a) function (PMID: 21462282). 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
0.31
BayesDel_addAF
Benign
0.0044
T
BayesDel_noAF
Benign
-0.23
CADD
Benign
23
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.43
T;T;.
Eigen
Benign
-0.23
Eigen_PC
Benign
-0.33
FATHMM_MKL
Uncertain
0.90
D
LIST_S2
Benign
0.76
T;T;T
M_CAP
Pathogenic
0.33
D
MetaRNN
Benign
0.33
T;T;T
MetaSVM
Benign
-0.38
T
PhyloP100
3.5
PrimateAI
Uncertain
0.65
T
PROVEAN
Benign
-2.3
N;.;N
REVEL
Benign
0.25
Sift
Benign
0.046
D;.;D
Sift4G
Benign
0.12
T;T;T
Polyphen
0.44
B;.;.
Vest4
0.34
MutPred
0.33
Gain of glycosylation at A20 (P = 0.0291);Gain of glycosylation at A20 (P = 0.0291);Gain of glycosylation at A20 (P = 0.0291);
MVP
0.81
MPC
0.49
ClinPred
0.61
D
GERP RS
3.0
PromoterAI
0.037
Neutral
Varity_R
0.22
gMVP
0.83
Mutation Taster
=22/78
disease causing

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

Other links and lift over

dbSNP: rs760065045; hg19: chr9-21974769; COSMIC: COSV58699768; COSMIC: COSV58699768; API