rs578143841

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PVS1_ModerateBS1

The NM_004618.5(TOP3A):​c.2779G>T​(p.Glu927*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000632 in 1,613,930 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: 𝑓 0.000052 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000064 ( 0 hom. )

Consequence

TOP3A
NM_004618.5 stop_gained

Scores

5
1

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.51

Publications

0 publications found
Variant links:
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]
TOP3A Gene-Disease associations (from GenCC):
  • microcephaly, growth restriction, and increased sister chromatid exchange 2
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P
  • progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 5
    Inheritance: AR Classification: STRONG, LIMITED Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0755 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
BS1
Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.0000525 (8/152392) while in subpopulation SAS AF = 0.00165 (8/4834). AF 95% confidence interval is 0.000823. There are 0 homozygotes in GnomAd4. There are 4 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004618.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
TOP3A
NM_004618.5
MANE Select
c.2779G>Tp.Glu927*
stop_gained
Exon 18 of 19NP_004609.1Q13472-1
TOP3A
NM_001320759.2
c.2494G>Tp.Glu832*
stop_gained
Exon 17 of 18NP_001307688.1Q13472-3

Ensembl Transcripts

Sel.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
TOP3A
ENST00000321105.10
TSL:1 MANE Select
c.2779G>Tp.Glu927*
stop_gained
Exon 18 of 19ENSP00000321636.5Q13472-1
TOP3A
ENST00000580095.5
TSL:1
c.2704G>Tp.Glu902*
stop_gained
Exon 18 of 19ENSP00000462790.1Q13472-2
TOP3A
ENST00000924978.1
c.2935G>Tp.Glu979*
stop_gained
Exon 19 of 20ENSP00000595037.1

Frequencies

GnomAD3 genomes
AF:
0.0000525
AC:
8
AN:
152274
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00165
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000179
AC:
45
AN:
250912
AF XY:
0.000243
show subpopulations
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000643
AC:
94
AN:
1461538
Hom.:
0
Cov.:
32
AF XY:
0.0000990
AC XY:
72
AN XY:
727016
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33468
American (AMR)
AF:
0.00
AC:
0
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39688
South Asian (SAS)
AF:
0.00105
AC:
91
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53368
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111764
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60372
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.494
Heterozygous variant carriers
0
6
12
19
25
31
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000525
AC:
8
AN:
152392
Hom.:
0
Cov.:
33
AF XY:
0.0000537
AC XY:
4
AN XY:
74524
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41596
American (AMR)
AF:
0.00
AC:
0
AN:
15306
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5190
South Asian (SAS)
AF:
0.00165
AC:
8
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10630
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68042
Other (OTH)
AF:
0.00
AC:
0
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.438
Heterozygous variant carriers
0
1
2
2
3
4
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.000181
AC:
22
Asia WGS
AF:
0.000289
AC:
1
AN:
3478

ClinVar

ClinVar submissions
Significance:Uncertain significance
Revision:criteria provided, single submitter
View on ClinVar
Pathogenic
VUS
Benign
Condition
-
1
-
Microcephaly, growth restriction, and increased sister chromatid exchange 2 (1)

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.32
D
BayesDel_noAF
Pathogenic
0.66
CADD
Pathogenic
40
DANN
Uncertain
1.0
Eigen
Pathogenic
1.1
Eigen_PC
Pathogenic
0.96
FATHMM_MKL
Pathogenic
1.0
D
PhyloP100
7.5
Vest4
0.25
GERP RS
5.7
Mutation Taster
=12/188
disease causing

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

Other links and lift over

dbSNP: rs578143841; hg19: chr17-18181037; API
For research and educational, non-commercial use only. Not for clinical or diagnostic use. GeneBe does not provide medical advice. Data use for AI modeling is prohibited: if used, the cost is $0.001 per byte of downloaded uncompressed data.