rs1419550675

Variant names:

• chr13-48381420-A-C
• rs1419550675
• NM_000321.3:c.1672A>C

Your query was ambiguous. Multiple possible variants found:

• chr13-48381420-A-C
• chr13-48381420-A-G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000321.3(RB1):​c.1672A>C​(p.Met558Leu) 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. M558V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: RB1 NM_000321.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.14
• Publications: 0 publications found

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]

RB1 Gene-Disease associations (from GenCC):

• hereditary retinoblastoma

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P, Ambry Genetics
• retinoblastoma

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• melanoma

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RB1	NM_000321.3	c.1672A>C	p.Met558Leu	missense_variant	Exon 17 of 27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.1672A>C	p.Met558Leu	missense_variant	Exon 17 of 27		NP_001394094.1
RB1	NM_001407166.1	c.1672A>C	p.Met558Leu	missense_variant	Exon 17 of 17		NP_001394095.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.1672A>C	p.Met558Leu	missense_variant	Exon 17 of 27	1	NM_000321.3	ENSP00000267163.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Retinoblastoma Uncertain:1

Nov 17, 2023

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 leucine, which is neutral and non-polar, at codon 558 of the RB1 protein (p.Met558Leu). 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: 458134). 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. -

Malignant tumor of urinary bladder Uncertain:1

Aug 04, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Mar 16, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.M558L variant (also known as c.1672A>C), located in coding exon 17 of the RB1 gene, results from an A to C substitution at nucleotide position 1672. The methionine at codon 558 is replaced by leucine, an amino acid with highly similar properties. This amino acid position is conserved. 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	Uncertain	0.47
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.030
CADD	Benign	23
DANN	Benign	0.88
DEOGEN2	Benign	0.37	T;.
Eigen	Benign	0.0018
Eigen_PC	Benign	0.21
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Benign	0.036	D
MetaRNN	Uncertain	0.56	D;D
MetaSVM	Benign	-0.55	T
MutationAssessor	Benign	0.49	N;.
PhyloP100		7.1
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-0.27	N;.
REVEL	Uncertain	0.48
Sift	Benign	0.59	T;.
Sift4G	Pathogenic	0.0	D;.
Polyphen		0.19	B;.
Vest4		0.69
MutPred		0.64		Gain of catalytic residue at L561 (P = 0);Gain of catalytic residue at L561 (P = 0);
MVP		0.91
MPC		1.2
ClinPred		0.88	D
GERP RS		5.3
PromoterAI		0.018	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.44
gMVP		0.72
Mutation Taster		=43/57	disease causing

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

Other links and lift over

dbSNP: rs1419550675; hg19: chr13-48955556;