9-21968235-G-C

Variant names:

• chr9-21968235-G-C
• rs1471079871
• NM_000077.5:c.465C>G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Moderate BP6 BP7

The NM_000077.5(CDKN2A):​c.465C>G​(p.Pro155Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,672 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. P155P) 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: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:2
• Conservation: PhyloP100: -0.988

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]

ENSG00000264545 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10632628).
• BP6: Variant 9-21968235-G-C is Benign according to our data. Variant chr9-21968235-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 825077.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=1}.
• BP7: Synonymous conserved (PhyloP=-0.988 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CDKN2A	NM_000077.5	c.465C>G	p.Pro155Pro	synonymous_variant	Exon 3 of 3	ENST00000304494.10	NP_000068.1
CDKN2A	NM_058195.4	c.*109C>G		3_prime_UTR_variant	Exon 3 of 3	ENST00000579755.2	NP_478102.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CDKN2A	ENST00000304494.10	c.465C>G	p.Pro155Pro	synonymous_variant	Exon 3 of 3	1	NM_000077.5	ENSP00000307101.5
CDKN2A	ENST00000579755	c.*109C>G		3_prime_UTR_variant	Exon 3 of 3	1	NM_058195.4	ENSP00000462950.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461672 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727148

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Nov 17, 2024

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 variant is located in the 3' untranslated region of the CDKN2A (p16INK4A) gene. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with CDKN2A-related disorders in the literature. This variant has not been identified 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. -

Feb 12, 2019

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Familial melanoma Benign:1

Dec 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.040
CADD	Benign	1.3
DANN	Benign	0.64
DEOGEN2	Benign	0.024	T
FATHMM_MKL	Benign	0.025	N
LIST_S2	Benign	0.26	T
M_CAP	Benign	0.0014	T
MetaRNN	Benign	0.11	T
Sift4G	Uncertain	0.021	D
Vest4		0.066
MVP		1.0
GERP RS		-3.3

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

LitVar

Other links and lift over

dbSNP: rs1471079871; hg19: chr9-21968234;