rs876659307

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_000077.5(CDKN2A):​c.443C>T​(p.Ala148Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,612,130 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A148P) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

CDKN2A
NM_000077.5 missense

Scores

2
16

Clinical Significance

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

Conservation

PhyloP100: -0.236

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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 9 benign, 41 uncertain in NM_000077.5
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.114471704).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CDKN2ANM_000077.5 linkc.443C>T p.Ala148Val missense_variant Exon 2 of 3 ENST00000304494.10 NP_000068.1 P42771-1K7PML8
CDKN2ANM_058195.4 linkc.*87C>T 3_prime_UTR_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.443C>T p.Ala148Val missense_variant Exon 2 of 3 1 NM_000077.5 ENSP00000307101.5 P42771-1
CDKN2AENST00000579755.2 linkc.*87C>T 3_prime_UTR_variant Exon 2 of 3 1 NM_058195.4 ENSP00000462950.1 Q8N726-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152248
Hom.:
0
Cov.:
32
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:
0.00
AC:
0
AN:
246924
AF XY:
0.00
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000274
AC:
4
AN:
1459882
Hom.:
0
Cov.:
31
AF XY:
0.00000275
AC XY:
2
AN XY:
726310
show subpopulations
African (AFR)
AF:
0.0000896
AC:
3
AN:
33464
American (AMR)
AF:
0.00
AC:
0
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86232
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51958
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5350
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111994
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60328
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
1
1
2
2
3
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:
152248
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74384
show subpopulations
African (AFR)
AF:
0.0000241
AC:
1
AN:
41480
American (AMR)
AF:
0.00
AC:
0
AN:
15292
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5196
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4838
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10618
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68034
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000378

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:3
Jul 22, 2021
Sema4, Sema4
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:curation

- -

Dec 17, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.A148V variant (also known as c.443C>T), located in coding exon 2 of the CDKN2A gene, results from a C to T substitution at nucleotide position 443. The alanine at codon 148 is replaced by valine, an amino acid with similar properties. This amino acid position is not 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. -

Jun 14, 2018
Color Diagnostics, LLC DBA Color Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
Sep 01, 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 does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Familial melanoma Uncertain:1
Dec 30, 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 valine, which is neutral and non-polar, at codon 148 of the CDKN2A (p16INK4a) protein (p.Ala148Val). 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: 231700). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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
0.11
BayesDel_addAF
Benign
-0.039
T
BayesDel_noAF
Benign
-0.29
CADD
Benign
12
DANN
Uncertain
0.98
DEOGEN2
Benign
0.11
T;.;.;.;.;T;.
Eigen
Benign
-1.1
Eigen_PC
Benign
-1.2
FATHMM_MKL
Benign
0.10
N
LIST_S2
Benign
0.70
T;.;T;.;T;T;T
M_CAP
Benign
0.050
D
MetaRNN
Benign
0.11
T;T;T;T;T;T;T
MetaSVM
Benign
-0.94
T
PhyloP100
-0.24
PrimateAI
Benign
0.41
T
PROVEAN
Benign
-0.80
N;.;N;.;.;.;.
REVEL
Benign
0.28
Sift
Uncertain
0.023
D;.;D;.;.;.;.
Sift4G
Benign
0.068
T;T;T;T;T;T;T
Polyphen
0.014
B;.;.;.;.;.;.
Vest4
0.14
MutPred
0.23
Loss of disorder (P = 0.1171);.;Loss of disorder (P = 0.1171);.;.;.;.;
MVP
0.90
MPC
0.39
ClinPred
0.049
T
GERP RS
-4.4
PromoterAI
-0.00070
Neutral
Varity_R
0.11
gMVP
0.40
Mutation Taster
=10/90
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
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: rs876659307; hg19: chr9-21970915; COSMIC: COSV58719138; API