20-37044131-C-G

Position:

• chr20-37044131-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_002895.5(RBL1):​c.1725G>C​(p.Trp575Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,344 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: RBL1 NM_002895.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.77

Genes affected

RBL1 (HGNC:9893): (RB transcriptional corepressor like 1) The protein encoded by this gene is similar in sequence and possibly function to the product of the retinoblastoma 1 (RB1) gene. The RB1 gene product is a tumor suppressor protein that appears to be involved in cell cycle regulation, as it is phosphorylated in the S to M phase transition and is dephosphorylated in the G1 phase of the cell cycle. Both the RB1 protein and the product of this gene can form a complex with adenovirus E1A protein and SV40 large T-antigen, with the SV40 large T-antigen binding only to the unphosphorylated form of each protein. In addition, both proteins can inhibit the transcription of cell cycle genes containing E2F binding sites in their promoters. Due to the sequence and biochemical similarities with the RB1 protein, it is thought that the protein encoded by this gene may also be a tumor suppressor. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
RBL1	NM_002895.5	c.1725G>C	p.Trp575Cys	missense_variant	13/22	ENST00000373664.8	NP_002886.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
RBL1	ENST00000373664.8	c.1725G>C	p.Trp575Cys	missense_variant	13/22	1	NM_002895.5	ENSP00000362768.3
RBL1	ENST00000344359.7	c.1725G>C	p.Trp575Cys	missense_variant	13/21	1		ENSP00000343646.3

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461344 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 726970

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

Alfa AF: 0.0000301 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 15, 2024

The c.1725G>C (p.W575C) alteration is located in exon 13 (coding exon 13) of the RBL1 gene. This alteration results from a G to C substitution at nucleotide position 1725, causing the tryptophan (W) at amino acid position 575 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.79	D;.
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.91	D
MutationAssessor	Pathogenic	3.1	M;M
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-12	D;D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.92
MutPred		0.86		Loss of helix (P = 0.1706);Loss of helix (P = 0.1706);
MVP		0.95
MPC		1.1
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.93

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

Publications

LitVar

Other links and lift over

dbSNP: rs953265198; hg19: chr20-35672534;