9-21994197-G-T

Variant names:

• chr9-21994197-G-T
• rs766676234
• NM_058195.4:c.135C>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Moderate BP6 BP7 BS2_Supporting

The NM_058195.4(CDKN2A):​c.135C>A​(p.Leu45Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000344 in 1,454,200 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. L45L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: CDKN2A NM_058195.4 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 0.248
• 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]

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]

ENSG00000264545 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.37).
• BP6: Variant 9-21994197-G-T is Benign according to our data. Variant chr9-21994197-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 532280.
• BP7: Synonymous conserved (PhyloP=0.248 with no splicing effect.
• BS2: High AC in GnomAdExome4 at 5 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_058195.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CDKN2A	NM_058195.4	MANE Plus Clinical	c.135C>A	p.Leu45Leu	synonymous	Exon 1 of 3	NP_478102.2	Q8N726-1
	CDKN2A	NM_001363763.2		c.-4+624C>A		intron	N/A	NP_001350692.1	P42771-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CDKN2A	ENST00000579755.2	TSL:1 MANE Plus Clinical	c.135C>A	p.Leu45Leu	synonymous	Exon 1 of 3	ENSP00000462950.1	Q8N726-1
	CDKN2A	ENST00000530628.2	TSL:5	c.135C>A	p.Leu45Leu	synonymous	Exon 1 of 3	ENSP00000432664.2	Q8N726-1
	CDKN2A	ENST00000494262.5	TSL:3	c.-175-144C>A		intron	N/A	ENSP00000464952.1	P42771-2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000344 AC: 5 AN: 1454200 Hom.: 0 Cov.: 32 AF XY: 0.00000414 AC XY: 3 AN XY: 723780

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44694

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86228

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 46144

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111858

Other (OTH) AF: 0.00 AC: 0 AN: 60262

GnomAD4 genome Cov.: 31

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	-	Familial melanoma (1)
-	-	1	Melanoma-pancreatic cancer syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.37
CADD	Benign	11
DANN	Benign	0.94
PhyloP100		0.25
PromoterAI		0.025	Neutral

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: rs766676234; hg19: chr9-21994196;