chr13-48453060-C-T

Position:

• chr13-48453060-C-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_Moderate BS2_Supporting

The NM_000321.3(RB1):​c.1763C>T​(p.Ser588Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000411 in 1,460,982 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. S588S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: RB1 NM_000321.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 3.72

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_benign. Variant got -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.25018004).
• BS2: High AC in GnomAdExome4 at 6 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RB1	NM_000321.3	c.1763C>T	p.Ser588Phe	missense_variant	18/27	ENST00000267163.6
RB1	NM_001407165.1	c.1763C>T	p.Ser588Phe	missense_variant	18/27

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RB1	ENST00000267163.6	c.1763C>T	p.Ser588Phe	missense_variant	18/27	1	NM_000321.3	P1
RB1	ENST00000650461.1	c.1763C>T	p.Ser588Phe	missense_variant	18/27
RB1	ENST00000643064.1	c.194+71617C>T		intron_variant
RB1	ENST00000480491.1	n.462C>T		non_coding_transcript_exon_variant	2/3	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460982 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 726818

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Retinoblastoma Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Nov 30, 2023	This missense variant replaces serine with phenylalanine at codon 588 of the RB1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with RB1-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 24, 2024	This sequence change replaces serine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 588 of the RB1 protein (p.Ser588Phe). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with RB1-related conditions. ClinVar contains an entry for this variant (Variation ID: 458136). 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 with a negative predictive value of 80%. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 05, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 23516486, Day alan_2006_Review) -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 21, 2022

The p.S588F variant (also known as c.1763C>T), located in coding exon 18 of the RB1 gene, results from a C to T substitution at nucleotide position 1763. The serine at codon 588 is replaced by phenylalanine, an amino acid with highly dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.085	D
BayesDel_noAF	Benign	-0.12
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.47	T;.
Eigen	Benign	0.063
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Uncertain	0.77	D
LIST_S2	Benign	0.77	T;T
M_CAP	Benign	0.036	D
MetaRNN	Benign	0.25	T;T
MetaSVM	Uncertain	-0.042	T
MutationAssessor	Benign	0.0	N;.
MutationTaster	Benign	0.86	N
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-0.84	N;.
REVEL	Uncertain	0.37
Sift	Benign	0.031	D;.
Sift4G	Uncertain	0.010	D;.
Polyphen		0.25	B;.
Vest4		0.30
MutPred		0.44		Gain of catalytic residue at E587 (P = 6e-04);Gain of catalytic residue at E587 (P = 6e-04);
MVP		0.83
MPC		0.63
ClinPred		0.61	D
GERP RS		5.8
Varity_R		0.29
gMVP		0.30

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs1555293637; hg19: chr13-49027196; COSMIC: COSV57321183;