Genetic Variant TOP1:p.His515Tyr (chr20-41114060-C-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_003286.4(TOP1):c.1543C>T(p.His515Tyr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,614,030 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

TOP1
NM_003286.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.29

Variant links:

Genes affected

TOP1 (HGNC:11986): (DNA topoisomerase I) 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 altering the topology of DNA. This gene is localized to chromosome 20 and has pseudogenes which reside on chromosomes 1 and 22. [provided by RefSeq, Jul 2008]

TOP1 links:

PLCG1-AS1 (HGNC:40450): (PLCG1 antisense RNA 1)

PLCG1-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.20883074).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TOP1	NM_003286.4 link	c.1543C>T	p.His515Tyr	missense_variant	Exon 15 of 21	ENST00000361337.3	NP_003277.1	P11387Q9BVT2
PLCG1-AS1	NR_109889.1 link	n.711-12771G>A		intron_variant	Intron 4 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TOP1	ENST00000361337.3 link	c.1543C>T	p.His515Tyr	missense_variant	Exon 15 of 21	1	NM_003286.4	ENSP00000354522.2		P11387

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152216

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461814

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727210

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152216

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.0000724

Gnomad4 AMR

AF:

0.0000654

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:

0.0000340

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Dec 19, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1543C>T (p.H515Y) alteration is located in exon 15 (coding exon 15) of the TOP1 gene. This alteration results from a C to T substitution at nucleotide position 1543, causing the histidine (H) at amino acid position 515 to be replaced by a tyrosine (Y). 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

Benign

0.079

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.48

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.48

Eigen

Benign

-0.021

Eigen_PC

Benign

0.19

FATHMM_MKL

Uncertain

0.92

LIST_S2

Uncertain

0.95

M_CAP

Benign

0.0041

MetaRNN

Benign

0.21

MetaSVM

Benign

-1.1

MutationAssessor

Benign

0.93

PrimateAI

Uncertain

0.75

PROVEAN

Uncertain

-4.0

REVEL

Benign

0.084

Sift

Benign

0.38

Sift4G

Benign

0.47

Polyphen

0.0070

Vest4

0.22

MutPred

0.49

Loss of disorder (P = 0.0893);

MVP

0.28

MPC

1.8

ClinPred

0.87

GERP RS

5.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.56

gMVP

0.68

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over