chr13-48459831-C-T

Position:

• chr13-48459831-C-T

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PVS1 PM2 PP3 PP5_Moderate

The NM_000321.3(RB1):​c.2104C>T​(p.Gln702Ter) variant causes a stop gained, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 30)
• Consequence: RB1 NM_000321.3 stop_gained, splice_region
• Scores: Splicing: ADA: 0.9997
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• 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 13 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
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 13-48459831-C-T is Pathogenic according to our data. Variant chr13-48459831-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 428683.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RB1	NM_000321.3	c.2104C>T	p.Gln702Ter	stop_gained, splice_region_variant	20/27	ENST00000267163.6
RB1	NM_001407165.1	c.2104C>T	p.Gln702Ter	stop_gained, splice_region_variant	20/27

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RB1	ENST00000267163.6	c.2104C>T	p.Gln702Ter	stop_gained, splice_region_variant	20/27	1	NM_000321.3	P1
RB1	ENST00000650461.1	c.2104C>T	p.Gln702Ter	stop_gained, splice_region_variant	20/27
RB1	ENST00000643064.1	c.194+78388C>T		intron_variant

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 30

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 18, 2013

The p.Q702Xpathogenic mutation (also known as c.2104C>T), located in coding exon 20 of theRB1gene, results from a C to T substitution at nucleotide position 2104. This changes the glutamine at codon 702 to a stop codon within exon 20. ​This mutation was described in a 13-year-old patient with bilateral retinoblastoma (Barbosa RH et al. Invest Ophthalmol Vis Sci. 2013;54(5):3184-94). In addition to the clinical data presented in the literature, and since premature stop codons are typically deleterious in nature, this alteration is interpreted as a disease-causing mutation (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	48
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	A
Vest4		0.99
GERP RS		5.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.060		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: rs1131690865; hg19: chr13-49033967; COSMIC: COSV57307527; COSMIC: COSV57307527;