13-48453111-T-C

Variant names:

• chr13-48453111-T-C
• rs1555293654
• NM_000321.3:c.1814T>C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000321.3(RB1):​c.1814T>C​(p.Met605Thr) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000206 in 1,458,906 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. 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. M605I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: RB1 NM_000321.3 missense, splice_region
• Scores: Splicing: ADA: 0.6131
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 4.98

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.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.32018209).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RB1	NM_000321.3	c.1814T>C	p.Met605Thr	missense_variant, splice_region_variant	Exon 18 of 27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.1814T>C	p.Met605Thr	missense_variant, splice_region_variant	Exon 18 of 27		NP_001394094.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.1814T>C	p.Met605Thr	missense_variant, splice_region_variant	Exon 18 of 27	1	NM_000321.3	ENSP00000267163.4
RB1	ENST00000650461.1	c.1814T>C	p.Met605Thr	missense_variant, splice_region_variant	Exon 18 of 27			ENSP00000497193.1
RB1	ENST00000643064.1	c.192+71668T>C		intron_variant	Intron 1 of 1			ENSP00000496005.1
RB1	ENST00000480491.1	n.513T>C		splice_region_variant, non_coding_transcript_exon_variant	Exon 2 of 3	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458906 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 725882

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Retinoblastoma Uncertain:2

Oct 23, 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 methionine with threonine at codon 605 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. -

Dec 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 605 of the RB1 protein (p.Met605Thr). 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: 458137). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

May 27, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1814T>C variant (also known as p.M605T), located in coding exon 18 of the RB1 gene, results from a T to C substitution at nucleotide position 1814. The amino acid change results in methionine to threonine at codon 605, an amino acid with similar properties. This change occurs in the last base pair of coding exon 18. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.83
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Uncertain	23
DANN	Benign	0.95
DEOGEN2	Uncertain	0.46	T;.
Eigen	Benign	0.043
Eigen_PC	Uncertain	0.23
FATHMM_MKL	Uncertain	0.86	D
LIST_S2	Uncertain	0.89	D;D
M_CAP	Benign	0.061	D
MetaRNN	Benign	0.32	T;T
MetaSVM	Uncertain	0.14	D
MutationAssessor	Benign	1.4	L;.
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-1.6	N;.
REVEL	Uncertain	0.40
Sift	Uncertain	0.028	D;.
Sift4G	Uncertain	0.0020	D;.
Polyphen		0.0070	B;.
Vest4		0.27
MutPred		0.32		Gain of catalytic residue at D604 (P = 0.0255);Gain of catalytic residue at D604 (P = 0.0255);
MVP		0.87
MPC		0.57
ClinPred		0.77	D
GERP RS		5.8
Varity_R		0.62
gMVP		0.34

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.61
dbscSNV1_RF	Benign	0.70
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: rs1555293654; hg19: chr13-49027247; COSMIC: COSV99031777;