rs759079385

Positions:

• chr13-48379612-C-A
• chr13-48379612-C-G
• chr13-48379612-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000321.3(RB1):​c.1351C>A​(p.Arg451Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. R451C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 30)
• Consequence: RB1 NM_000321.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.46

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]

LOC112268118 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_000321.3
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RB1	NM_000321.3	c.1351C>A	p.Arg451Ser	missense_variant	14/27	ENST00000267163.6
LOC112268118	XR_002957522.2	n.40+223G>T		intron_variant, non_coding_transcript_variant
RB1	NM_001407165.1	c.1351C>A	p.Arg451Ser	missense_variant	14/27
RB1	NM_001407166.1	c.1351C>A	p.Arg451Ser	missense_variant	14/17

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RB1	ENST00000267163.6	c.1351C>A	p.Arg451Ser	missense_variant	14/27	1	NM_000321.3	P1
RB1	ENST00000650461.1	c.1351C>A	p.Arg451Ser	missense_variant	14/27

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 30

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

Invitae

Oct 04, 2022

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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 not expected to disrupt RB1 protein function. This variant has not been reported in the literature in individuals affected with RB1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 451 of the RB1 protein (p.Arg451Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Uncertain	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.64	D;.
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Benign	0.055	D
MetaRNN	Uncertain	0.66	D;D
MetaSVM	Uncertain	0.47	D
MutationAssessor	Benign	2.0	M;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.75	T
PROVEAN	Benign	-2.3	N;.
REVEL	Pathogenic	0.66
Sift	Benign	0.13	T;.
Sift4G	Uncertain	0.0060	D;.
Polyphen		1.0	D;.
Vest4		0.73
MutPred		0.65		Gain of catalytic residue at R451 (P = 0.001);Gain of catalytic residue at R451 (P = 0.001);
MVP		0.89
MPC		1.4
ClinPred		0.87	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.78
gMVP		0.61

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.42		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.42		Position offset: -18

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr13-48953748;