dbSNP rs1555286503: RB1:c.1333-2A>G (chr13-48379592-A-G) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong

The NM_000321.3(RB1):c.1333-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

Genomes: not found (cov: 30)

Consequence

RB1
NM_000321.3 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 8.47

Variant links:

Genes affected

RB1 (HGNC:9884): (RB transcriptional corepressor 1) The protein encoded by this gene is a negative regulator of the cell cycle and was the first tumor suppressor gene found. The encoded protein also stabilizes constitutive heterochromatin to maintain the overall chromatin structure. The active, hypophosphorylated form of the protein binds transcription factor E2F1. Defects in this gene are a cause of childhood cancer retinoblastoma (RB), bladder cancer, and osteogenic sarcoma. [provided by RefSeq, Jul 2008]

RB1 links:

LOC112268118 (HGNC:):

LOC112268118 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.020452099 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.5, offset of -33, new splice context is: attgtgattttctaaaatAGcag. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 13-48379592-A-G is Pathogenic according to our data. Variant chr13-48379592-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 458120.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
RB1	NM_000321.3 link	c.1333-2A>G	splice_acceptor_variant, intron_variant	Intron 13 of 26	ENST00000267163.6	NP_000312.2	P06400A0A024RDV3
RB1	NM_001407165.1 link	c.1333-2A>G	splice_acceptor_variant, intron_variant	Intron 13 of 26		NP_001394094.1
RB1	NM_001407166.1 link	c.1333-2A>G	splice_acceptor_variant, intron_variant	Intron 13 of 16		NP_001394095.1
LOC112268118	XR_002957522.2 link	n.40+243T>C	intron_variant	Intron 1 of 2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6 link	c.1333-2A>G		splice_acceptor_variant, intron_variant	Intron 13 of 26	1	NM_000321.3	ENSP00000267163.4		P06400
RB1	ENST00000650461.1 link	c.1333-2A>G		splice_acceptor_variant, intron_variant	Intron 13 of 26			ENSP00000497193.1		A0A3B3IS71

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Cov.:

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Retinoblastoma

Pathogenic:2

Dec 15, 2020

Department of Pediatrics, Memorial Sloan Kettering Cancer Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Mar 05, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Loss-of-function variants in RB1 are known to be pathogenic. This particular variant has been reported in several individuals affected with retinoblastoma in the literature (PMID: 12541220) and in the Leiden Open-source Variation Database (PMID: 21520333). This variant is also known as 1471-2A>G in the literature. For these reasons, this variant has been classified as Pathogenic. This sequence change affects an acceptor splice site in intron 13 of the RB1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.38

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Pathogenic

1.2

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

1.0

GERP RS

5.7

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.96

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.96

Position offset: 2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

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