13-48303724-G-A

Variant names:

• chr13-48303724-G-A
• rs387906520
• NM_000321.3:c.-189G>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000321.3(RB1):​c.-189G>A variant causes a upstream gene change. The variant allele was found at a frequency of 0.00000128 in 780,022 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000013 (0 hom.)
• Consequence: RB1 NM_000321.3 upstream_gene
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.76
• 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-DT (HGNC:42778): (RB1 divergent transcript)

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.23).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RB1	NM_000321.3	c.-189G>A		upstream_gene_variant		ENST00000267163.6	NP_000312.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.-189G>A		upstream_gene_variant		1	NM_000321.3	ENSP00000267163.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000128 AC: 1 AN: 780022 Hom.: 0 Cov.: 11 AF XY: 0.00000256 AC XY: 1 AN XY: 390144

African (AFR) AF: 0.00 AC: 0 AN: 15096

American (AMR) AF: 0.00 AC: 0 AN: 12014

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 14948

East Asian (EAS) AF: 0.00 AC: 0 AN: 25312

South Asian (SAS) AF: 0.00 AC: 0 AN: 49094

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 28890

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2584

European-Non Finnish (NFE) AF: 0.00000168 AC: 1 AN: 596264

Other (OTH) AF: 0.00 AC: 0 AN: 35820

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Retinoblastoma Uncertain:1

Jun 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant occurs in a non-coding region of the RB1 gene. It does not change the encoded amino acid sequence of the RB1 protein. 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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. Experimental studies and prediction algorithms are not available or were not evaluated, and the effect of this variant on mRNA splicing is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.23
CADD	Benign	22
DANN	Uncertain	0.98
PhyloP100		3.8
PromoterAI		-0.79	Under-expression

Splicing

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

Other links and lift over

dbSNP: rs387906520; hg19: chr13-48877860;