13-48307380-A-G

Variant names:

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS2

The NM_000321.3(RB1):c.238A>G(p.Lys80Glu) variant causes a missense change. The variant allele was found at a frequency of 0.0000118 in 1,613,454 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K80N) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

RB1
NM_000321.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 4.28

Publications

4 publications found

Variant links:

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

RB1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -7 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.19015402).

BP6

Variant 13-48307380-A-G is Benign according to our data. Variant chr13-48307380-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 410925.

BS2

High AC in GnomAdExome4 at 18 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
RB1	NM_000321.3 link	c.238A>G	p.Lys80Glu	missense_variant	Exon 2 of 27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1 link	c.238A>G	p.Lys80Glu	missense_variant	Exon 2 of 27		NP_001394094.1
RB1	NM_001407166.1 link	c.238A>G	p.Lys80Glu	missense_variant	Exon 2 of 17		NP_001394095.1
RB1	NM_001407167.1 link	c.238A>G	p.Lys80Glu	missense_variant	Exon 2 of 3		NP_001394096.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6 link	c.238A>G	p.Lys80Glu	missense_variant	Exon 2 of 27	1	NM_000321.3	ENSP00000267163.4

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152238

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251344

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1461216

Hom.:

Cov.:

AF XY:

0.0000165

AC XY:

AN XY:

726970

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33452

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26114

East Asian (EAS)

AF:

0.00

AC:

AN:

39554

South Asian (SAS)

AF:

0.00

AC:

AN:

86246

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53404

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000162

AC:

AN:

1111618

Other (OTH)

AF:

0.00

AC:

AN:

60350

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.458

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152238

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74372

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41458

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5204

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68050

Other (OTH)

AF:

0.00

AC:

AN:

2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Retinoblastoma

Uncertain:1Benign:1

Sep 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 27, 2024

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 lysine with glutamic acid at codon 80 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 been reported in a pediatric individual affected with Ewing's sarcoma (PMID: 26580448). This variant has been identified in 2/251344 chromosomes 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.

Hereditary cancer-predisposing syndrome

Uncertain:1

Apr 19, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.K80E variant (also known as c.238A>G), located in coding exon 2 of the RB1 gene, results from an A to G substitution at nucleotide position 238. The lysine at codon 80 is replaced by glutamic acid, an amino acid with similar properties. This variant has been reported in 1/1120 pediatric cancer patients who underwent whole genome sequencing and/or whole-exome sequencing; this patient was diagnosed with Ewing's sarcoma (Zhang J et al. N Engl J Med, 2015 Dec;373:2336-2346). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

0.0047

BayesDel_noAF

Benign

-0.22

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.28

T;.;.

Eigen

Benign

-0.061

Eigen_PC

Benign

0.085

FATHMM_MKL

Uncertain

0.87

LIST_S2

Benign

0.73

T;T;T

M_CAP

Benign

0.027

MetaRNN

Benign

0.19

T;T;T

MetaSVM

Benign

-0.75

MutationAssessor

Benign

0.97

L;.;.

PhyloP100

4.3

PrimateAI

Uncertain

0.61

PROVEAN

Benign

-0.40

N;.;.

REVEL

Benign

0.23

Sift

Benign

0.31

T;.;.

Sift4G

Benign

0.18

T;.;.

Vest4

0.62

ClinPred

0.34

GERP RS

4.7

Varity_R

0.25

gMVP

0.19

Mutation Taster

=75/25

polymorphism

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over