20-41121785-G-A

Variant summary

Our verdict is Benign. Variant got -15 ACMG points: 0P and 15B. BP4_Moderate BP6_Very_Strong BP7 BS2

The NM_003286.4(TOP1):c.2040G>A(p.Thr680=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000191 in 1,613,916 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.000085 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00020 (2 hom.)
• Consequence: TOP1 NM_003286.4 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: 0.500

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]

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

ACMG classification

Verdict is Benign. Variant got -15 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.41).
• BP6: Variant 20-41121785-G-A is Benign according to our data. Variant chr20-41121785-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 749280.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=0.5 with no splicing effect.
• BS2: High AC in GnomAd at 13 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TOP1	NM_003286.4	c.2040G>A	p.Thr680=	synonymous_variant	19/21	ENST00000361337.3
PLCG1-AS1	NR_109889.1	n.710+11702C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TOP1	ENST00000361337.3	c.2040G>A	p.Thr680=	synonymous_variant	19/21	1	NM_003286.4	P1
PLCG1-AS1	ENST00000454626.1	n.713+11702C>T		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes AF: 0.0000854 AC: 13 AN: 152216 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.0000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00186

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.000374 AC: 94 AN: 251488 Hom.: 0 AF XY: 0.000427 AC XY: 58 AN XY: 135916

Gnomad AFR exome AF: 0.000185

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00284

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000202 AC: 295 AN: 1461582 Hom.: 2 Cov.: 30 AF XY: 0.000274 AC XY: 199 AN XY: 727120

Gnomad4 AFR exome AF: 0.0000896

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00274

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000315

Gnomad4 OTH exome AF: 0.000298

GnomAD4 genome AF: 0.0000853 AC: 13 AN: 152334 Hom.: 1 Cov.: 33 AF XY: 0.0000805 AC XY: 6 AN XY: 74496

Gnomad4 AFR AF: 0.0000722

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00186

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.0000193 Hom.: 0

Bravo AF: 0.0000756

Asia WGS AF: 0.00202 AC: 7 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jun 08, 2018

- -

TOP1-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Dec 30, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.41
Cadd	Benign	12
Dann	Benign	0.74

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: rs550250396; hg19: chr20-39750425; COSMIC: COSV63693651;