NM_000321.3:c.2627G>A

Variant names:

• chr13-48476807-G-A
• rs767232453
• NM_000321.3:c.2627G>A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM1 BS2_Supporting

The NM_000321.3(RB1):​c.2627G>A​(p.Arg876His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,461,372 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• 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: 9.04

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 1 ACMG points.

• PM1: In a region_of_interest Domain C; mediates interaction with E4F1 (size 157) in uniprot entity RB_HUMAN there are 8 pathogenic changes around while only 0 benign (100%) in NM_000321.3
• 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 rank	MANE	Protein	UniProt
RB1	NM_000321.3	c.2627G>A	p.Arg876His	missense_variant	Exon 25 of 27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.2627G>A	p.Arg876His	missense_variant	Exon 25 of 27		NP_001394094.1
RB1	NM_001407168.1	c.77G>A	p.Arg26His	missense_variant	Exon 2 of 4		NP_001394097.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.2627G>A	p.Arg876His	missense_variant	Exon 25 of 27	1	NM_000321.3	ENSP00000267163.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251320 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135814

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1461372 Hom.: 0 Cov.: 30 AF XY: 0.00000550 AC XY: 4 AN XY: 726988

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.000109

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Retinoblastoma Uncertain:3

Jul 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 876 of the RB1 protein (p.Arg876His). This variant is present in population databases (rs767232453, gnomAD 0.003%). 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: 458154). 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. -

Jun 08, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with histidine at codon 876 of the RB1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, 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 been identified in 1/251320 chromosomes 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. -

Apr 28, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Feb 28, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R876H variant (also known as c.2627G>A), located in coding exon 25 of the RB1 gene, results from a G to A substitution at nucleotide position 2627. The arginine at codon 876 is replaced by histidine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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	Uncertain	0.38
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.49	T;.
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.93	D;D
M_CAP	Benign	0.084	D
MetaRNN	Uncertain	0.67	D;D
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Benign	1.4	L;.
PrimateAI	Uncertain	0.72	T
PROVEAN	Benign	-1.2	N;.
REVEL	Uncertain	0.64
Sift	Benign	0.061	T;.
Sift4G	Benign	0.089	T;.
Polyphen		0.84	P;.
Vest4		0.88
MutPred		0.65		Gain of catalytic residue at E880 (P = 0.0151);Gain of catalytic residue at E880 (P = 0.0151);
MVP		0.94
MPC		0.74
ClinPred		0.59	D
GERP RS		5.8
Varity_R		0.73
gMVP		0.33

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: rs767232453; hg19: chr13-49050943;