3-25598360-A-G

Position:

• chr3-25598360-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001330700.2(TOP2B):​c.4828T>C​(p.Phe1610Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TOP2B NM_001330700.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.51

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 2 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.32475698).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TOP2B	NM_001330700.2	c.4828T>C	p.Phe1610Leu	missense_variant	36/36	ENST00000264331.9	NP_001317629.1
TOP2B	NM_001068.3	c.4813T>C	p.Phe1605Leu	missense_variant	36/36		NP_001059.2
TOP2B	XM_011534057.4	c.4717T>C	p.Phe1573Leu	missense_variant	35/35		XP_011532359.1
TOP2B	XM_047448821.1	c.4702T>C	p.Phe1568Leu	missense_variant	35/35		XP_047304777.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TOP2B	ENST00000264331.9	c.4828T>C	p.Phe1610Leu	missense_variant	36/36	5	NM_001330700.2	ENSP00000264331.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

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

Aug 19, 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. This sequence change replaces phenylalanine with leucine at codon 1605 of the TOP2B protein (p.Phe1605Leu). The phenylalanine residue is moderately conserved and there is a small physicochemical difference between phenylalanine and leucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with TOP2B-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Benign	-0.036	T
BayesDel_noAF	Benign	-0.29
CADD	Benign	20
DANN	Benign	0.89
DEOGEN2	Benign	0.041	T;.
Eigen	Benign	-0.24
Eigen_PC	Benign	0.036
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.79	T;T
M_CAP	Benign	0.010	T
MetaRNN	Benign	0.32	T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.0	L;.
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	-0.36	N;N
REVEL	Benign	0.15
Sift	Benign	1.0	T;T
Sift4G	Benign	0.99	T;T
Polyphen		0.0050	B;B
Vest4		0.69
MutPred		0.45		Gain of relative solvent accessibility (P = 0.0023);.;
MVP		0.22
MPC		0.058
ClinPred		0.55	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.13

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-25639851;