Genetic Variant TOP2B:p.Glu1612dup (chr3-25598351-A-ACTC) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 1P and 4B. PM4_SupportingBS2

The NM_001330700.2(TOP2B):c.4834_4836dupGAG(p.Glu1612dup) variant causes a conservative inframe insertion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,612,160 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. E1612E) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

TOP2B
NM_001330700.2 conservative_inframe_insertion

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.723

Publications

0 publications found

Variant links:

Genes affected

TOP2B (HGNC:11990): (DNA topoisomerase II beta) This gene encodes a DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This nuclear enzyme is involved in processes such as chromosome condensation, chromatid separation, and the relief of torsional stress that occurs during DNA transcription and replication. It catalyzes the transient breaking and rejoining of two strands of duplex DNA which allows the strands to pass through one another, thus altering the topology of DNA. Two forms of this enzyme exist as likely products of a gene duplication event. The gene encoding this form, beta, is localized to chromosome 3 and the alpha form is localized to chromosome 17. The gene encoding this enzyme functions as the target for several anticancer agents and a variety of mutations in this gene have been associated with the development of drug resistance. Reduced activity of this enzyme may also play a role in ataxia-telangiectasia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2016]

TOP2B Gene-Disease associations (from GenCC):

B-cell immunodeficiency, distal limb anomalies, and urogenital malformations
Inheritance: AD Classification: STRONG, MODERATE Submitted by: ClinGen, Illumina, Ambry Genetics, PanelApp Australia
neurodevelopmental disorder
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

TOP2B links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM4

Nonframeshift variant in NON repetitive region in NM_001330700.2. Strenght limited to Supporting due to length of the change: 1aa.

BS2

High AC in GnomAdExome4 at 20 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001330700.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TOP2B	NM_001330700.2	MANE Select	c.4834_4836dupGAG	p.Glu1612dup	conservative_inframe_insertion	Exon 36 of 36	NP_001317629.1	Q02880-1
	TOP2B	NM_001068.3		c.4819_4821dupGAG	p.Glu1607dup	conservative_inframe_insertion	Exon 36 of 36	NP_001059.2	Q59H80

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TOP2B	ENST00000264331.9	TSL:5 MANE Select	c.4834_4836dupGAG	p.Glu1612dup	conservative_inframe_insertion	Exon 36 of 36	ENSP00000264331.4	Q02880-1
TOP2B	ENST00000435706.7	TSL:1	c.4819_4821dupGAG	p.Glu1607dup	conservative_inframe_insertion	Exon 36 of 36	ENSP00000396704.2
TOP2B	ENST00000424225.2	TSL:1	c.4735_4737dupGAG	p.Glu1579dup	conservative_inframe_insertion	Exon 36 of 36	ENSP00000391112.2

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152068

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000323

AC:

AN:

248040

AF XY:

0.0000149

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000146

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000558

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000178

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000137

AC:

AN:

1460092

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

726282

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33412

American (AMR)

AF:

0.000157

AC:

AN:

44542

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26096

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39656

South Asian (SAS)

AF:

0.00

AC:

AN:

85882

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53368

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00000990

AC:

AN:

1111056

Other (OTH)

AF:

0.0000166

AC:

AN:

60320

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

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:

0.0000132

AC:

AN:

152068

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74272

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:

41400

American (AMR)

AF:

0.00

AC:

AN:

15260

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10582

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68020

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 = 0.0296732), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

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:

0.0000113

EpiCase

AF:

0.00

EpiControl

AF:

0.0000594

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.72

Mutation Taster

=71/29

polymorphism

(source)

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over