13-48373494-T-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000321.3(RB1):​c.1215+2T>G variant causes a splice donor, intron change. 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: 32)

Consequence

RB1
NM_000321.3 splice_donor, intron

Scores

4
2
1
Splicing: ADA: 1.000
2

Clinical Significance

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

Conservation

PhyloP100: 5.96
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]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 13-48373494-T-G is Pathogenic according to our data. Variant chr13-48373494-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 410921.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
RB1NM_000321.3 linkc.1215+2T>G splice_donor_variant, intron_variant Intron 12 of 26 ENST00000267163.6 NP_000312.2 P06400A0A024RDV3
RB1NM_001407165.1 linkc.1215+2T>G splice_donor_variant, intron_variant Intron 12 of 26 NP_001394094.1
RB1NM_001407166.1 linkc.1215+2T>G splice_donor_variant, intron_variant Intron 12 of 16 NP_001394095.1
LOC112268118XR_002957522.2 linkn.121+666A>C intron_variant Intron 2 of 2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
RB1ENST00000267163.6 linkc.1215+2T>G splice_donor_variant, intron_variant Intron 12 of 26 1 NM_000321.3 ENSP00000267163.4 P06400
RB1ENST00000650461.1 linkc.1215+2T>G splice_donor_variant, intron_variant Intron 12 of 26 ENSP00000497193.1 A0A3B3IS71

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
Cov.:
25
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Retinoblastoma Pathogenic:1
Jan 11, 2021
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This sequence change affects a donor splice site in intron 12 of the RB1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in RB1 are known to be pathogenic (PMID: 17096365). This variant is not present in population databases (ExAC no frequency). Disruption of this splice site has been observed in individual(s) with bilateral retinoblastoma (PMID: 12541220, 28193182). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 410921). For these reasons, this variant has been classified as Pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1
Jan 26, 2022
Ambry Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The c.1215+2T>G intronic pathogenic mutation results from a T to G substitution two nucleotides after coding exon 12 in the RB1 gene. This alteration has been observed in at least one individual with a personal and/or family history that is consistent with RB1-related disease (Ambry internal data). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site; however, direct evidence is insufficient at this time (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.63
D
BayesDel_noAF
Pathogenic
0.29
CADD
Pathogenic
28
DANN
Uncertain
0.99
Eigen
Pathogenic
1.0
Eigen_PC
Pathogenic
0.88
FATHMM_MKL
Uncertain
0.97
D
GERP RS
5.4
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.1

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
0.98
Details are displayed if max score is > 0.2
DS_DL_spliceai
0.98
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.

Other links and lift over

dbSNP: rs1060503074; hg19: chr13-48947630; COSMIC: COSV57294535; API