3-25598383-C-G

Position:

• chr3-25598383-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_001330700.2(TOP2B):​c.4805G>C​(p.Arg1602Pro) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,192 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: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TOP2B NM_001330700.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.38

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TOP2B. . Gene score misZ 3.8634 (greater than the threshold 3.09). Trascript score misZ 3.6879 (greater than threshold 3.09). GenCC has associacion of gene with B-cell immunodeficiency, distal limb anomalies, and urogenital malformations.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.811

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TOP2B	NM_001330700.2	c.4805G>C	p.Arg1602Pro	missense_variant	36/36	ENST00000264331.9	NP_001317629.1
TOP2B	NM_001068.3	c.4790G>C	p.Arg1597Pro	missense_variant	36/36		NP_001059.2
TOP2B	XM_011534057.4	c.4694G>C	p.Arg1565Pro	missense_variant	35/35		XP_011532359.1
TOP2B	XM_047448821.1	c.4679G>C	p.Arg1560Pro	missense_variant	35/35		XP_047304777.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TOP2B	ENST00000264331.9	c.4805G>C	p.Arg1602Pro	missense_variant	36/36	5	NM_001330700.2	ENSP00000264331.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461192 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726852

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.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 29, 2023

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 1597 of the TOP2B protein (p.Arg1597Pro). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TOP2B-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Benign	0.39	T;.
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Benign	0.083	D
MetaRNN	Pathogenic	0.81	D;D
MetaSVM	Benign	-0.32	T
MutationAssessor	Benign	0.90	L;.
PrimateAI	Uncertain	0.78	T
PROVEAN	Uncertain	-3.2	D;D
REVEL	Uncertain	0.56
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.021	D;D
Polyphen		1.0	D;D
Vest4		0.58
MutPred		0.78		Gain of glycosylation at T1600 (P = 0.0069);.;
MVP		0.45
MPC		0.39
ClinPred		0.95	D
GERP RS		5.6
Varity_R		0.81
gMVP		0.54

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-25639874;