chr13-48362957-G-C

Position:

• chr13-48362957-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP5_Moderate

The ENST00000267163.6(RB1):​c.861G>C​(p.Glu287Asp) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E287G) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: RB1 ENST00000267163.6 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.83

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-48362957-G-C is Pathogenic according to our data. Variant chr13-48362957-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 458186.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
RB1	NM_000321.3	c.861G>C	p.Glu287Asp	missense_variant, splice_region_variant	8/27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.861G>C	p.Glu287Asp	missense_variant, splice_region_variant	8/27		NP_001394094.1
RB1	NM_001407166.1	c.861G>C	p.Glu287Asp	missense_variant, splice_region_variant	8/17		NP_001394095.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.861G>C	p.Glu287Asp	missense_variant, splice_region_variant	8/27	1	NM_000321.3	ENSP00000267163.4
RB1	ENST00000650461.1	c.861G>C	p.Glu287Asp	missense_variant, splice_region_variant	8/27			ENSP00000497193.1
RB1	ENST00000467505.5	n.*229G>C		downstream_gene_variant		1		ENSP00000434702.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Retinoblastoma Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 20, 2017

Nucleotide substitutions within the consensus splice site are relatively common causes of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of nucleotide changes on RNA splicing suggest that this variant may alter RNA splicing. RT-PCR analysis of patient lymphocyte RNA showed that this variant caused skipping of exon 8 (PMID: 11317357). For these reasons, this variant has been classified as Pathogenic. This variant has been reported in multiple individuals affected with bilateral retinoblastoma (PMID: 11317357, 26539030, 22084214). This sequence change replaces glutamic acid with aspartic acid at codon 287 of the RB1 protein (p.Glu287Asp). The glutamic acid residue is highly conserved and there is a small physicochemical difference between glutamic acid and aspartic acid. This variant also falls at the last nucleotide of exon 8 of the RB1 coding sequence, which is part of the consensus splice site for this exon. This variant is not present in population databases (ExAC no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.61
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.030
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.53	D;.
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.78	T;T
M_CAP	Uncertain	0.28	D
MetaRNN	Uncertain	0.60	D;D
MetaSVM	Pathogenic	0.87	D
MutationAssessor	Uncertain	2.3	M;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-1.8	N;.
REVEL	Uncertain	0.63
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;.
Polyphen		1.0	D;.
Vest4		0.70
MutPred		0.50		Loss of methylation at K289 (P = 0.0647);Loss of methylation at K289 (P = 0.0647);
MVP		0.93
MPC		0.66
ClinPred		0.97	D
GERP RS		5.2
Varity_R		0.74
gMVP		0.70

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.75		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.73		Position offset: 48
DS_DL_spliceai		0.75		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555284956; hg19: chr13-48937093; COSMIC: COSV99922896; COSMIC: COSV99922896;