rs1131690876

Positions:

• chr13-48381321-GC-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000321.3(RB1):​c.1575delC​(p.Phe526fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: RB1 NM_000321.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.57

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 Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-48381321-GC-G is Pathogenic according to our data. Variant chr13-48381321-GC-G is described in ClinVar as [Pathogenic]. Clinvar id is 428697.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr13-48381321-GC-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
RB1	NM_000321.3	c.1575delC	p.Phe526fs	frameshift_variant	17/27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.1575delC	p.Phe526fs	frameshift_variant	17/27		NP_001394094.1
RB1	NM_001407166.1	c.1575delC	p.Phe526fs	frameshift_variant	17/17		NP_001394095.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.1575delC	p.Phe526fs	frameshift_variant	17/27	1	NM_000321.3	ENSP00000267163.4
RB1	ENST00000650461.1	c.1575delC	p.Phe526fs	frameshift_variant	17/27			ENSP00000497193.1
RB1	ENST00000643064.1	c.72delC	p.Phe25fs	frameshift_variant	1/2			ENSP00000496005.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Retinoblastoma Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genetic Diagnostic Laboratory, University of Pennsylvania School of Medicine

May 20, 2024

Case and Pedigree Information: BILATERAL CASES:0, UNILATERAL CASES:1, TOTAL CASES:1, PEDIGREES:1. ACMG Codes Applied:PVS1, PM2 -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 23, 2017

The c.1575delC pathogenic mutation, located in coding exon 17 of the RB1 gene, results from a deletion of one nucleotide at nucleotide position 1575, causing a translational frameshift with a predicted alternate stop codon (p.F526Lfs*6). This mutation, designated as g.78159delC, was previously reported in a 12 month old child of Spanish ancestry who was diagnosed with bilateral retinoblastoma and whose father had a history of bilateral retinoblastoma (Alonso J et al. Hum Mutat. 2005 Jan;25(1):99). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1131690876; hg19: chr13-48955457;