Genetic Variant TOP3B:p.Arg824Cys (chr22-21957233-G-A) – ACMG Classification: Uncertain_significance (1 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2BP4

The NM_001282112.2(TOP3B):c.2470C>T(p.Arg824Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000134 in 1,346,988 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 Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 27)

Exomes 𝑓: 0.000013 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

TOP3B
NM_001282112.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.94

Variant links:

Genes affected

TOP3B (HGNC:11993): (DNA topoisomerase III beta) This gene encodes a DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This enzyme catalyzes the transient breaking and rejoining of a single strand of DNA which allows the strands to pass through one another, thus relaxing the supercoils and altering the topology of DNA. The enzyme interacts with DNA helicase SGS1 and plays a role in DNA recombination, cellular aging and maintenance of genome stability. Low expression of this gene may be related to higher survival rates in breast cancer patients. This gene has a pseudogene on chromosome 22. Alternate splicing results in multiple transcript variants. Additional alternatively spliced transcript variants of this gene have been described, but their full-length nature is not known. [provided by RefSeq, Aug 2013]

TOP3B links:

PPM1F-AS1 (HGNC:40888): (PPM1F antisense RNA 1)

PPM1F-AS1 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.37704718).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TOP3B	NM_001282112.2 link	c.2470C>T	p.Arg824Cys	missense_variant	Exon 18 of 18	ENST00000357179.10	NP_001269041.1	O95985-1A0A024R1C2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TOP3B	ENST00000357179.10 link	c.2470C>T	p.Arg824Cys	missense_variant	Exon 18 of 18	1	NM_001282112.2	ENSP00000349705.5		O95985-1

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

151370

Hom.:

Cov.:

FAILED QC

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000210

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000295

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000262

AC:

AN:

114646

Hom.:

AF XY:

0.0000324

AC XY:

AN XY:

61640

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 SAS exome

AF:

0.000122

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000230

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000134

AC:

AN:

1346988

Hom.:

Cov.:

AF XY:

0.0000195

AC XY:

AN XY:

666790

show subpopulations

Gnomad4 AFR exome

AF:

0.0000327

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000775

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000868

Gnomad4 OTH exome

AF:

0.0000357

GnomAD4 genome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.0000264

AC:

AN:

151486

Hom.:

Cov.:

AF XY:

0.0000270

AC XY:

AN XY:

73966

show subpopulations

Gnomad4 AFR

AF:

0.0000242

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000210

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000295

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 01, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2470C>T (p.R824C) alteration is located in exon 18 (coding exon 17) of the TOP3B gene. This alteration results from a C to T substitution at nucleotide position 2470, causing the arginine (R) at amino acid position 824 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

Uncertain

0.42

BayesDel_addAF

Benign

-0.19

BayesDel_noAF

Benign

-0.28

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.45

T;T

Eigen

Uncertain

0.46

Eigen_PC

Uncertain

0.41

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.95

.;D

M_CAP

Benign

0.044

MetaRNN

Benign

0.38

T;T

MetaSVM

Benign

-0.96

MutationAssessor

Uncertain

2.6

M;M

PrimateAI

Pathogenic

0.83

PROVEAN

Uncertain

-3.9

D;D

REVEL

Benign

0.14

Sift

Uncertain

0.0020

D;D

Sift4G

Uncertain

0.0030

D;D

Polyphen

1.0

D;D

Vest4

0.47

MutPred

0.23

Loss of MoRF binding (P = 0.0155);Loss of MoRF binding (P = 0.0155);

MVP

0.69

MPC

3.3

ClinPred

0.81

GERP RS

4.0

Varity_R

0.26

gMVP

0.48

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over