chr20-438793-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -11 ACMG points: 0P and 11B. BP4_ModerateBP6_Very_StrongBP7

The NM_144628.4(TBC1D20):c.1005G>A(p.Gln335Gln) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000342 in 1,614,266 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0017 ( 1 hom., cov: 33)

Exomes 𝑓: 0.00020 ( 1 hom. )

Consequence

TBC1D20
NM_144628.4 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5

Conservation

PhyloP100: 2.09

Publications

1 publications found

Variant links:

Genes affected

TBC1D20 (HGNC:16133): (TBC1 domain family member 20) This gene encodes a protein that belongs to a family of GTPase activator proteins of Rab-like small GTPases. The encoded protein and its cognate GTPase, Rab1, bind the nonstructural protein 5A (NS5A) of the hepatitis C virus (HCV) to mediate viral replication. Depletion of this protein inhibits replication of the virus and HCV infection. Mutations in this gene are associated with Warburg micro syndrome 4. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2014]

TBC1D20 Gene-Disease associations (from GenCC):

Warburg micro syndrome 4
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
Warburg micro syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

TBC1D20 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -11 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.45).

BP6

Variant 20-438793-C-T is Benign according to our data. Variant chr20-438793-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 436943.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=2.09 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_144628.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBC1D20	NM_144628.4	MANE Select	c.1005G>A	p.Gln335Gln	synonymous	Exon 8 of 8	NP_653229.1
	TBC1D20	NR_111901.2		n.1133G>A		non_coding_transcript_exon	Exon 8 of 10

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TBC1D20	ENST00000354200.5	TSL:1 MANE Select	c.1005G>A	p.Gln335Gln	synonymous	Exon 8 of 8	ENSP00000346139.4
TBC1D20	ENST00000461304.5	TSL:1	n.1005G>A		non_coding_transcript_exon	Exon 8 of 10	ENSP00000432280.1
TBC1D20	ENST00000679895.1		c.1101G>A	p.Gln367Gln	synonymous	Exon 9 of 9	ENSP00000505197.1

Frequencies

GnomAD3 genomes

AF:

0.00175

AC:

266

AN:

152258

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00617

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000327

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:

0.0000294

Gnomad OTH

AF:

0.00143

GnomAD2 exomes

AF:

0.000409

AC:

102

AN:

249410

AF XY:

0.000304

show subpopulations

Gnomad AFR exome

AF:

0.00585

Gnomad AMR exome

AF:

0.0000867

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000269

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.000196

AC:

286

AN:

1461890

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

117

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.00681

AC:

228

AN:

33480

American (AMR)

AF:

0.000134

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000324

AC:

AN:

1112008

Other (OTH)

AF:

0.000248

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.485

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

<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:

0.00175

AC:

266

AN:

152376

Hom.:

Cov.:

AF XY:

0.00160

AC XY:

119

AN XY:

74516

show subpopulations

African (AFR)

AF:

0.00616

AC:

256

AN:

41590

American (AMR)

AF:

0.000327

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68040

Other (OTH)

AF:

0.00142

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.501

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

<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:

0.000736

Hom.:

Bravo

AF:

0.00184

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:3

Jun 10, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Breakthrough Genomics, Breakthrough Genomics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:not provided

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TBC1D20-related disorder

Benign:1

Sep 14, 2024

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

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).

not specified

Benign:1

Jan 08, 2016

Genetic Services Laboratory, University of Chicago

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.45

CADD

Benign

9.4

(source)

DANN

Benign

0.90

PhyloP100

2.1

Mutation Taster

=100/0

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over