chr3-25598369-C-A

Position:

• chr3-25598369-C-A

Variant summary

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

The NM_001330700.2(TOP2B):​c.4819G>T​(p.Val1607Leu) variant causes a missense change. The variant allele was found at a frequency of 0.0000131 in 152,208 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 33)
• 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 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=0.2936386).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TOP2B	NM_001330700.2	c.4819G>T	p.Val1607Leu	missense_variant	36/36	ENST00000264331.9	NP_001317629.1
TOP2B	NM_001068.3	c.4804G>T	p.Val1602Leu	missense_variant	36/36		NP_001059.2
TOP2B	XM_011534057.4	c.4708G>T	p.Val1570Leu	missense_variant	35/35		XP_011532359.1
TOP2B	XM_047448821.1	c.4693G>T	p.Val1565Leu	missense_variant	35/35		XP_047304777.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TOP2B	ENST00000264331.9	c.4819G>T	p.Val1607Leu	missense_variant	36/36	5	NM_001330700.2	ENSP00000264331.4

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152208 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000483

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248604 Hom.: 0 AF XY: 0.00000741 AC XY: 1 AN XY: 134888

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.00

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152208 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74356

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000302

ExAC AF: 0.00000828 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 23, 2023

The c.4804G>T (p.V1602L) alteration is located in exon 36 (coding exon 36) of the TOP2B gene. This alteration results from a G to T substitution at nucleotide position 4804, causing the valine (V) at amino acid position 1602 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.67
BayesDel_addAF	Benign	-0.037	T
BayesDel_noAF	Benign	-0.11
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.14	T;.
Eigen	Uncertain	0.24
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D;D
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.29	T;T
MetaSVM	Benign	-0.94	T
MutationAssessor	Benign	1.0	L;.
PrimateAI	Pathogenic	0.88	D
PROVEAN	Benign	-1.3	N;N
REVEL	Benign	0.18
Sift	Uncertain	0.018	D;D
Sift4G	Benign	0.20	T;T
Polyphen		0.69	P;P
Vest4		0.59
MutPred		0.57		Gain of glycosylation at Y1609 (P = 0.004);.;
MVP		0.36
MPC		0.13
ClinPred		0.53	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.23
gMVP		0.34

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

LitVar

Other links and lift over

dbSNP: rs764317223; hg19: chr3-25639860;