chr9-21974756-C-A

Position:

• chr9-21974756-C-A

Variant summary

Our verdict is Benign. Variant got -11 ACMG points: 2P and 13B. PM2 BP4_Strong BP6_Very_Strong BP7

The NM_000077.5(CDKN2A):​c.72G>T​(p.Arg24=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,458,286 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. R24R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CDKN2A NM_000077.5 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: -1.26

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]

ACMG classification

Verdict is Benign. Variant got -11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.48).
• BP6: Variant 9-21974756-C-A is Benign according to our data. Variant chr9-21974756-C-A is described in ClinVar as [Likely_benign]. Clinvar id is 463511.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-1.26 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CDKN2A	NM_000077.5	c.72G>T	p.Arg24=	synonymous_variant	1/3	ENST00000304494.10
CDKN2A	NM_058195.4	c.194-3548G>T		intron_variant		ENST00000579755.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CDKN2A	ENST00000304494.10	c.72G>T	p.Arg24=	synonymous_variant	1/3	1	NM_000077.5	P2
CDKN2A	ENST00000579755.2	c.194-3548G>T		intron_variant		1	NM_058195.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458286 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 725632

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 17, 2019	- -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	May 25, 2017	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. -

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 21, 2018

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Familial melanoma Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 25, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.48
CADD	Benign	6.6
DANN	Benign	0.91

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1449870708; hg19: chr9-21974755;