NM_001330700.2:c.4856_4867dupATGTTGATTTTG

Variant names:

• chr3-25598320-G-GCAAAATCAACAT
• NM_001330700.2:c.4856_4867dupATGTTGATTTTG

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM4

The NM_001330700.2(TOP2B):​c.4856_4867dupATGTTGATTTTG​(p.Asp1619_Phe1622dup) variant causes a conservative inframe insertion change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A1623A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TOP2B NM_001330700.2 conservative_inframe_insertion
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.47
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM4: Nonframeshift variant in NON repetitive region in NM_001330700.2.

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.4856_4867dupATGTTGATTTTG	p.Asp1619_Phe1622dup	conservative_inframe_insertion	Exon 36 of 36	NP_001317629.1	Q02880-1
	TOP2B	NM_001068.3		c.4841_4852dupATGTTGATTTTG	p.Asp1614_Phe1617dup	conservative_inframe_insertion	Exon 36 of 36	NP_001059.2	Q59H80

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TOP2B	ENST00000264331.9	TSL:5 MANE Select	c.4856_4867dupATGTTGATTTTG	p.Asp1619_Phe1622dup	conservative_inframe_insertion	Exon 36 of 36	ENSP00000264331.4	Q02880-1
	TOP2B	ENST00000435706.7	TSL:1	c.4841_4852dupATGTTGATTTTG	p.Asp1614_Phe1617dup	conservative_inframe_insertion	Exon 36 of 36	ENSP00000396704.2
	TOP2B	ENST00000424225.2	TSL:1	c.4757_4768dupATGTTGATTTTG	p.Asp1586_Phe1589dup	conservative_inframe_insertion	Exon 36 of 36	ENSP00000391112.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.5

Splicing

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

Other links and lift over

hg19: chr3-25639811;