rs1555286687

Positions:

• chr13-48381295-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000321.3(RB1):​c.1547G>C​(p.Trp516Ser) variant causes a missense 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. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W516R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: RB1 NM_000321.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.60

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.947

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RB1	NM_000321.3	c.1547G>C	p.Trp516Ser	missense_variant	17/27	ENST00000267163.6
RB1	NM_001407165.1	c.1547G>C	p.Trp516Ser	missense_variant	17/27
RB1	NM_001407166.1	c.1547G>C	p.Trp516Ser	missense_variant	17/17

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RB1	ENST00000267163.6	c.1547G>C	p.Trp516Ser	missense_variant	17/27	1	NM_000321.3	P1
RB1	ENST00000650461.1	c.1547G>C	p.Trp516Ser	missense_variant	17/27
RB1	ENST00000643064.1	c.47G>C	p.Trp16Ser	missense_variant	1/2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Retinoblastoma Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 14, 2023

This variant is not present in population databases (gnomAD no frequency). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt RB1 protein function. ClinVar contains an entry for this variant (Variation ID: 458131). This variant has not been reported in the literature in individuals affected with RB1-related conditions. This sequence change replaces tryptophan, which is neutral and slightly polar, with serine, which is neutral and polar, at codon 516 of the RB1 protein (p.Trp516Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.92	D;.
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;D
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.95	D;D
MetaSVM	Uncertain	0.79	D
MutationAssessor	Uncertain	2.5	M;.
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-11	D;.
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;.
Polyphen		1.0	D;.
Vest4		0.91
MutPred		0.79		Gain of catalytic residue at L512 (P = 0.0054);Gain of catalytic residue at L512 (P = 0.0054);
MVP		0.98
MPC		1.7
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.98
gMVP		0.84

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555286687; hg19: chr13-48955431;