Variant chr17-18274804-ATCTGT-A details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_004618.5(TOP3A):c.2999_3003delACAGA(p.Asn1000fs) variant causes a frameshift change. The variant allele was found at a frequency of 0.000013 in 1,613,486 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 30)

Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

TOP3A
NM_004618.5 frameshift

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.15

Variant links:

Genes affected

TOP3A (HGNC:11992): (DNA topoisomerase III alpha) 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 reducing the number of supercoils and altering the topology of DNA. This enzyme forms a complex with BLM which functions in the regulation of recombination in somatic cells. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2016]

TOP3A links:

TOP3A (HGNC:):

TOP3A links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.00233 CDS is truncated, and there are 0 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TOP3A	NM_004618.5 linkuse as main transcript	c.2999_3003delACAGA	p.Asn1000fs	frameshift_variant	19/19	ENST00000321105.10	NP_004609.1	Q13472-1
TOP3A	NM_001320759.2 linkuse as main transcript	c.2714_2718delACAGA	p.Asn905fs	frameshift_variant	18/18		NP_001307688.1	Q13472-3
TOP3A	XM_047436633.1 linkuse as main transcript	c.2078_2082delACAGA	p.Asn693fs	frameshift_variant	17/17		XP_047292589.1
TOP3A	XM_047436634.1 linkuse as main transcript	c.2078_2082delACAGA	p.Asn693fs	frameshift_variant	17/17		XP_047292590.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TOP3A	ENST00000321105.10 linkuse as main transcript	c.2999_3003delACAGA	p.Asn1000fs	frameshift_variant	19/19	1	NM_004618.5	ENSP00000321636.5		Q13472-1

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152170

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000589

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

GnomAD3 exomes

AF:

0.0000239

AC:

AN:

251236

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135778

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.000327

GnomAD4 exome

AF:

0.00000753

AC:

AN:

1461316

Hom.:

AF XY:

0.00000550

AC XY:

AN XY:

726976

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000112

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:

0.00000450

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152170

Hom.:

Cov.:

AF XY:

0.0000941

AC XY:

AN XY:

74354

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000589

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000982

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 07, 2021

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant has not been reported in the literature in individuals affected with TOP3A-related conditions. This variant is present in population databases (rs770056993, gnomAD 0.01%). This sequence change results in a frameshift in the TOP3A gene (p.Asn1000Metfs*5). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 2 amino acid(s) of the TOP3A protein and extend the protein by 2 additional amino acid residues. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

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