rs778503152

Variant names:

• chr13-48463822-A-G
• rs778503152
• NM_000321.3:c.2198A>G

Your query was ambiguous. Multiple possible variants found:

• chr13-48463822-A-G
• chr13-48463822-A-T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM2 PM5 BP4 BP6

The NM_000321.3(RB1):​c.2198A>G​(p.His733Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000276 in 1,447,484 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts 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. H733L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000028 (0 hom.)
• Consequence: RB1 NM_000321.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 8.77
• Publications: 1 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
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-48463821-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 126797.Status of the report is no_assertion_criteria_provided, 0 stars.
• BP4: Computational evidence support a benign effect (MetaRNN=0.4108753).
• BP6: Variant 13-48463822-A-G is Benign according to our data. Variant chr13-48463822-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 527908.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RB1	NM_000321.3	c.2198A>G	p.His733Arg	missense_variant	Exon 21 of 27	ENST00000267163.6	NP_000312.2
RB1	NM_001407165.1	c.2198A>G	p.His733Arg	missense_variant	Exon 21 of 27		NP_001394094.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RB1	ENST00000267163.6	c.2198A>G	p.His733Arg	missense_variant	Exon 21 of 27	1	NM_000321.3	ENSP00000267163.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 250948 AF XY: 0.00

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: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000276 AC: 4 AN: 1447484 Hom.: 0 Cov.: 28 AF XY: 0.00000416 AC XY: 3 AN XY: 720972

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

African (AFR) AF: 0.00 AC: 0 AN: 33168

American (AMR) AF: 0.00 AC: 0 AN: 44686

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26028

East Asian (EAS) AF: 0.00 AC: 0 AN: 39444

South Asian (SAS) AF: 0.00 AC: 0 AN: 85926

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53384

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5718

European-Non Finnish (NFE) AF: 0.00000364 AC: 4 AN: 1099200

Other (OTH) AF: 0.00 AC: 0 AN: 59930

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00585934), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000282 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Retinoblastoma Uncertain:1 Benign:1

Feb 05, 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 histidine with arginine at codon 733 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 an individual in the the Leiden Open-source Variation Database (LOVD, http://rb1-lovd.d-lohmann.de/). This variant has been identified in 1/250948 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. -

Sep 16, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 19, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.H733R variant (also known as c.2198A>G), located in coding exon 21 of the RB1 gene, results from an A to G substitution at nucleotide position 2198. The histidine at codon 733 is replaced by arginine, an amino acid with highly similar properties. This alteration is described in one study as not having an effect on splicing (Zhang K et al. Hum. Mutat., 2008 Apr;29:475-84). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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	Uncertain	0.35
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.57	D;.
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	D;D
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.41	T;T
MetaSVM	Uncertain	0.26	D
MutationAssessor	Benign	0.14	N;.
PhyloP100		8.8
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-1.0	N;.
REVEL	Uncertain	0.48
Sift	Benign	0.030	D;.
Sift4G	Uncertain	0.0070	D;.
Polyphen		0.85	P;.
Vest4		0.31
MutPred		0.53		Gain of MoRF binding (P = 0.0241);Gain of MoRF binding (P = 0.0241);
MVP		0.79
MPC		0.58
ClinPred		0.52	D
GERP RS		6.2
Varity_R		0.64
gMVP		0.53
Mutation Taster		=20/80	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs778503152; hg19: chr13-49037958;