NM_058195.4:c.79A>C

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_ModerateBS2

The NM_058195.4(CDKN2A):c.79A>C(p.Ile27Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000243 in 1,606,486 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 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. I27M) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000026 ( 0 hom. )

Consequence

CDKN2A
NM_058195.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: -0.641

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 links:

CDKN2B-AS1 (HGNC:34341): (CDKN2B antisense RNA 1) This gene is located within the CDKN2B-CDKN2A gene cluster at chromosome 9p21. The gene product is a functional RNA molecule that interacts with polycomb repressive complex-1 (PRC1) and -2 (PRC2), leading to epigenetic silencing of other genes in this cluster. This region is a significant genetic susceptibility locus for cardiovascular disease, and has also been linked to a number of other pathologies, including several cancers, intracranial aneurysm, type-2 diabetes, periodontitis, Alzheimer's disease, endometriosis, frailty in the elderly, and glaucoma. Multiple alternatively processed transcript variants have been detected, some of which may take the form of circular RNA molecules (PMID:21151960). [provided by RefSeq, May 2014]

CDKN2B-AS1 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 -6 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.16358876).

BS2

High AC in GnomAdExome4 at 38 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
CDKN2A	NM_058195.4 link	c.79A>C	p.Ile27Leu	missense_variant	Exon 1 of 3	ENST00000579755.2	NP_478102.2
CDKN2A	NM_001363763.2 link	c.-4+568A>C		intron_variant	Intron 1 of 2		NP_001350692.1
CDKN2A	XM_047422597.1 link	c.-4+294A>C		intron_variant	Intron 1 of 2		XP_047278553.1
LOC124902130	XR_007061436.1 link	n.-225A>C		upstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CDKN2A	ENST00000579755.2 link	c.79A>C	p.Ile27Leu	missense_variant	Exon 1 of 3	1	NM_058195.4	ENSP00000462950.1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151934

Hom.:

Cov.:

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:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000426

AC:

AN:

234548

AF XY:

0.00000771

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:

0.00000940

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000261

AC:

AN:

1454552

Hom.:

Cov.:

AF XY:

0.0000235

AC XY:

AN XY:

723676

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33436

American (AMR)

AF:

0.00

AC:

AN:

44534

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26046

East Asian (EAS)

AF:

0.00

AC:

AN:

39658

South Asian (SAS)

AF:

0.00

AC:

AN:

86114

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48044

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000342

AC:

AN:

1110808

Other (OTH)

AF:

0.00

AC:

AN:

60152

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

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:

151934

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74210

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41376

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5106

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

312

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67964

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

EpiCase

AF:

0.00

EpiControl

AF:

0.0000595

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Melanoma-pancreatic cancer syndrome

Uncertain:2

Apr 21, 2023

Myriad Genetics, Inc.

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk.

Jul 13, 2016

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

not provided

Uncertain:1

Aug 07, 2019

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); n silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 26104880)

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

Uncertain:1

Feb 02, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Hereditary cancer-predisposing syndrome

Uncertain:1

Aug 30, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.I27L variant (also known as c.79A>C), located in coding exon 1 of the CDKN2A (p14ARF) gene, results from an A to C substitution at nucleotide position 79. The isoleucine at codon 27 is replaced by leucine, an amino acid with highly similar properties. This alteration has been reported in an individual with acute lymphoblastic leukemia (Xu H et al. Nat Commun, 2015 Jun;6:7553). 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. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Familial melanoma

Uncertain:1

Oct 28, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 27 of the CDKN2A (p14ARF) protein (p.Ile27Leu). This variant is present in population databases (no rsID available, gnomAD 0.001%). This missense change has been observed in individual(s) with acute lymphoblastic leukemia (PMID: 26104880). ClinVar contains an entry for this variant (Variation ID: 371881). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest 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.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.39

BayesDel_addAF

Benign

-0.094

BayesDel_noAF

Benign

-0.37

CADD

Benign

(source)

DANN

Benign

0.84

DEOGEN2

Benign

0.031

T;T

Eigen

Benign

-1.3

Eigen_PC

Benign

-1.4

FATHMM_MKL

Benign

0.062

LIST_S2

Benign

0.0

.;T

M_CAP

Uncertain

0.14

MetaRNN

Benign

0.16

T;T

MetaSVM

Benign

-0.96

MutationAssessor

Benign

0.0

.;.

PhyloP100

-0.64

PrimateAI

Uncertain

0.76

PROVEAN

Benign

0.0

.;N

REVEL

Benign

0.0

Sift

Pathogenic

0.0

.;T

Sift4G

Benign

0.22

T;T

Vest4

0.45

ClinPred

0.11

GERP RS

-8.2

PromoterAI

0.060

Neutral

(source)

Mutation Taster

=5/95

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over