chr17-18274928-C-A

Variant names:

• chr17-18274928-C-A
• rs541672157
• NM_004618.5:c.2880G>T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_004618.5(TOP3A):​c.2880G>T​(p.Ser960Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 30)
• Consequence: TOP3A NM_004618.5 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.908

Genes affected

TOP3A (HGNC:11992): (DNA topoisomerase III alpha) This gene encodes a DNA topoisomerase, an enzyme that controls and alters the topologic states of DNA during transcription. This enzyme catalyzes the transient breaking and rejoining of a single strand of DNA which allows the strands to pass through one another, thus reducing the number of supercoils and altering the topology of DNA. This enzyme forms a complex with BLM which functions in the regulation of recombination in somatic cells. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Mar 2016]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.67).
• BP7: Synonymous conserved (PhyloP=-0.908 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TOP3A	NM_004618.5	c.2880G>T	p.Ser960Ser	synonymous_variant	Exon 19 of 19	ENST00000321105.10	NP_004609.1
TOP3A	NM_001320759.2	c.2595G>T	p.Ser865Ser	synonymous_variant	Exon 18 of 18		NP_001307688.1
TOP3A	XM_047436633.1	c.1959G>T	p.Ser653Ser	synonymous_variant	Exon 17 of 17		XP_047292589.1
TOP3A	XM_047436634.1	c.1959G>T	p.Ser653Ser	synonymous_variant	Exon 17 of 17		XP_047292590.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TOP3A	ENST00000321105.10	c.2880G>T	p.Ser960Ser	synonymous_variant	Exon 19 of 19	1	NM_004618.5	ENSP00000321636.5

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251484 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135922

Gnomad AFR exome AF: 0.00

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 30

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.67
CADD	Benign	0.27
DANN	Benign	0.41
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs541672157; hg19: chr17-18178242;