rs878853646

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_000077.5(CDKN2A):​c.253G>T​(p.Ala85Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000312 in 1,604,348 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. A85T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000028 ( 0 hom. )

Consequence

CDKN2A
NM_000077.5 missense

Scores

7
10
1

Clinical Significance

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

Conservation

PhyloP100: 7.31

Publications

11 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: Likely_pathogenic. The variant received 6 ACMG points.

PM1
In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 15 uncertain in NM_000077.5
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.904

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CDKN2ANM_000077.5 linkc.253G>T p.Ala85Ser missense_variant Exon 2 of 3 ENST00000304494.10 NP_000068.1 P42771-1K7PML8
CDKN2ANM_058195.4 linkc.296G>T p.Arg99Leu missense_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
CDKN2AENST00000304494.10 linkc.253G>T p.Ala85Ser missense_variant Exon 2 of 3 1 NM_000077.5 ENSP00000307101.5 P42771-1
CDKN2AENST00000579755.2 linkc.296G>T p.Arg99Leu missense_variant Exon 2 of 3 1 NM_058195.4 ENSP00000462950.1 Q8N726-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152236
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.000193
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:
0.00000432
AC:
1
AN:
231476
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.0000694
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000275
AC:
4
AN:
1452112
Hom.:
0
Cov.:
31
AF XY:
0.00000277
AC XY:
2
AN XY:
722786
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33436
American (AMR)
AF:
0.00
AC:
0
AN:
44656
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26072
East Asian (EAS)
AF:
0.0000504
AC:
2
AN:
39678
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86172
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
44866
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5442
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111538
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60252
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.500
Heterozygous variant carriers
0
1
2
2
3
4
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00000657
AC:
1
AN:
152236
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74382
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41472
American (AMR)
AF:
0.00
AC:
0
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.000193
AC:
1
AN:
5192
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68040
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
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

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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.:
0
Bravo
AF:
0.00000378

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
Jun 08, 2021
Color Diagnostics, LLC DBA Color Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This missense variant replaces alanine with serine at codon 85 of the CDKN2A protein (p16INK4A). Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 1/231476 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. -

Oct 04, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.A85S variant (also known as c.253G>T), located in coding exon 2 of the CDKN2A gene, results from a G to T substitution at nucleotide position 253. The alanine at codon 85 is replaced by serine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

not specified Uncertain:1
Jan 23, 2023
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: CDKN2A c.253G>T (p.Ala85Ser) results in a conservative amino acid change located in the ankyrin repeat-containing domain (IPR036770) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.3e-06 in 231476 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.253G>T in individuals affected with Cutaneous Malignant Melanoma and no experimental evidence demonstrating its impact on protein function have been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014, and all laboratories classified the variant as uncertain significance. Additionally, variants occurring at the same nucleotide (c.253G>A, p.Ala85Thr and c.253G>C, p.Ala85Pro) and within the same codon (c.254C>T, p.Ala85Val) have all been reported as uncertain significance in ClinVar. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Melanoma and neural system tumor syndrome Uncertain:1
Aug 12, 2023
Baylor Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
Sep 15, 2022
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 has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Familial melanoma Uncertain:1
Nov 24, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The CDKN2A gene encodes two different proteins, p16INK4a and p14ARF, which are translated from alternative transcripts with different open reading frames. Both transcripts have been analyzed. We report either the variant with the higher classification or default to the CDKN2A (p16INK4a) variant. This report therefore includes the details for the CDKN2A (p16INK4a) variant. This sequence change replaces alanine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 85 of the CDKN2A (p16INK4a) protein (p.Ala85Ser). 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. This variant is also known as c.296G>T (p.Arg99Leu) in the CDKN2A (p14ARF) transcript. ClinVar contains an entry for this variant (Variation ID: 532289). 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
Uncertain
0.43
BayesDel_addAF
Pathogenic
0.42
D
BayesDel_noAF
Uncertain
0.070
CADD
Pathogenic
27
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.44
T;T;.;.;.;.;T;.
Eigen
Pathogenic
0.73
Eigen_PC
Pathogenic
0.77
FATHMM_MKL
Pathogenic
0.97
D
LIST_S2
Uncertain
0.97
D;D;.;D;.;D;D;D
M_CAP
Pathogenic
0.63
D
MetaRNN
Pathogenic
0.90
D;D;D;D;D;D;D;D
MetaSVM
Uncertain
0.27
D
PhyloP100
7.3
PrimateAI
Uncertain
0.67
T
PROVEAN
Uncertain
-2.7
D;.;.;D;.;.;.;.
REVEL
Pathogenic
0.80
Sift
Uncertain
0.0020
D;.;.;D;.;.;.;.
Sift4G
Uncertain
0.0050
D;T;D;D;D;D;D;D
Polyphen
0.99
D;.;.;.;.;.;.;.
Vest4
0.69
MutPred
0.82
Gain of disorder (P = 0.0608);Gain of disorder (P = 0.0608);.;Gain of disorder (P = 0.0608);.;.;.;.;
MVP
0.93
MPC
1.2
ClinPred
0.96
D
GERP RS
5.9
PromoterAI
0.0056
Neutral
Varity_R
0.43
gMVP
0.82
Mutation Taster
=1/99
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: rs878853646; hg19: chr9-21971105; COSMIC: COSV58705440; COSMIC: COSV58705440; API