9-21971024-C-G

Variant names:

• chr9-21971024-C-G
• rs587782797
• NM_000077.5:c.335G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_000077.5(CDKN2A):​c.335G>C​(p.Arg112Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. R112C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CDKN2A NM_000077.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.412
• Publications: 0 publications found

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

ENSG00000264545 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 44 uncertain in NM_000077.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-21971025-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 233484.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.898

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CDKN2A	NM_000077.5	c.335G>C	p.Arg112Pro	missense_variant	Exon 2 of 3	ENST00000304494.10	NP_000068.1
CDKN2A	NM_058195.4	c.378G>C	p.Pro126Pro	synonymous_variant	Exon 2 of 3	ENST00000579755.2	NP_478102.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CDKN2A	ENST00000304494.10	c.335G>C	p.Arg112Pro	missense_variant	Exon 2 of 3	1	NM_000077.5	ENSP00000307101.5
CDKN2A	ENST00000579755.2	c.378G>C	p.Pro126Pro	synonymous_variant	Exon 2 of 3	1	NM_058195.4	ENSP00000462950.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Jun 24, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R112P variant (also known as c.335G>C), located in coding exon 2 of the CDKN2A gene, results from a G to C substitution at nucleotide position 335. The arginine at codon 112 is replaced by proline, an amino acid with dissimilar properties. Of note, this alteration is also known as c.378G>C (p.P126P)in the p14(ARF) isoform. This alteration has been reported in 1 of 702 Spanish patients with either multiple primary melanoma or familial melanoma (Potrony M et al, J. Am. Acad. Dermatol. 2014 Nov; 71(5):888-95). This amino acid position is well 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.49	T;T;.;.;.;.;T;.
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.91	D;D;.;D;.;D;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.27	T
PhyloP100		0.41
PrimateAI	Benign	0.42	T
PROVEAN	Pathogenic	-4.6	D;.;.;D;.;.;.;.
REVEL	Uncertain	0.58
Sift	Benign	0.050	D;.;.;D;.;.;.;.
Sift4G	Benign	0.14	T;T;T;T;T;T;T;T
Polyphen		1.0	D;.;.;.;.;.;.;.
Vest4		0.77
MutPred		0.60		Loss of MoRF binding (P = 0.0065);Loss of MoRF binding (P = 0.0065);.;Loss of MoRF binding (P = 0.0065);.;.;.;.;
MVP		1.0
MPC		1.5
ClinPred		0.96	D
GERP RS		5.9
PromoterAI		0.025	Neutral
Varity_R		0.85
gMVP		0.81
Mutation Taster		=0/100	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

Other links and lift over

dbSNP: rs587782797; hg19: chr9-21971023; COSMIC: COSV58697439;