NM_000321.3:c.1332+1G>A

Variant names:

• chr13-48377035-G-A
• rs587778846
• NM_000321.3:c.1332+1G>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000321.3(RB1):​c.1332+1G>A variant causes a splice donor, 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: 32)
• Consequence: RB1 NM_000321.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 8.75
• Publications: 2 publications found

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 Gene-Disease associations (from GenCC):

• hereditary retinoblastoma

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P, Ambry Genetics
• retinoblastoma

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• melanoma

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics

LOC112268118 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.041980624 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-48377035-G-A is Pathogenic according to our data. Variant chr13-48377035-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 126834.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
RB1	NM_000321.3	c.1332+1G>A		splice_donor_variant, intron_variant	Intron 13 of 26	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.1332+1G>A		splice_donor_variant, intron_variant	Intron 13 of 26		NP_001394094.1
RB1	NM_001407166.1	c.1332+1G>A		splice_donor_variant, intron_variant	Intron 13 of 16		NP_001394095.1
LOC112268118	XR_002957522.2	n.41-2795C>T		intron_variant	Intron 1 of 2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.1332+1G>A		splice_donor_variant, intron_variant	Intron 13 of 26	1	NM_000321.3	ENSP00000267163.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Retinoblastoma Pathogenic:2

May 20, 2024

Genetic Diagnostic Laboratory, University of Pennsylvania School of Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Case and Pedigree Information: BILATERAL CASES:0, UNILATERAL CASES:2, TOTAL CASES:2, PEDIGREES:2. ACMG Codes Applied:PVS1, PM2 -

Jul 10, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 13 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 (gnomAD no frequency). Disruption of this splice site has been observed in individuals with retinoblastoma (PMID: 8651278, 12402348, 15605413). This variant is also known as IVS13+1G>A, g.73870G>A or g.73869+1G>A. ClinVar contains an entry for this variant (Variation ID: 126834). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Jun 29, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant expected to result in aberrant splicing, although in the absence of functional evidence the actual effect of this sequence change is unknown.; Not observed at significant frequency in large population cohorts (gnomAD); Also known as g.73869+1G>A; This variant is associated with the following publications: (PMID: 25525159, 15605413, 12402348, 8651278, 23516486, 30996590) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		8.7
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=0/100	disease causing (ClinVar)

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: -1

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

Other links and lift over

dbSNP: rs587778846; hg19: chr13-48951171; COSMIC: COSV57303394; COSMIC: COSV57303394;