Genetic Variant TBC1D20:p.Ala381Ala (chr20-438655-C-T) – ACMG Classification: Likely_benign (-6 pts)

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_StrongBP6BP7

The NM_144628.4(TBC1D20):c.1143G>A(p.Ala381Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000602 in 1,614,186 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00037 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00063 ( 0 hom. )

Consequence

TBC1D20
NM_144628.4 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:2

Conservation

PhyloP100: -1.31

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: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia
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: Likely_benign. The variant received -6 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.64).

BP6

Variant 20-438655-C-T is Benign according to our data. Variant chr20-438655-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 212369.

BP7

Synonymous conserved (PhyloP=-1.31 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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TBC1D20	NM_144628.4	MANE Select	c.1143G>A	p.Ala381Ala	synonymous	Exon 8 of 8	NP_653229.1	Q96BZ9-1
	TBC1D20	NR_111901.2		n.1271G>A		non_coding_transcript_exon	Exon 8 of 10

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TBC1D20	ENST00000354200.5	TSL:1 MANE Select	c.1143G>A	p.Ala381Ala	synonymous	Exon 8 of 8	ENSP00000346139.4	Q96BZ9-1
TBC1D20	ENST00000461304.5	TSL:1	n.1143G>A		non_coding_transcript_exon	Exon 8 of 10	ENSP00000432280.1	Q96BZ9-1
TBC1D20	ENST00000679895.1		c.1239G>A	p.Ala413Ala	synonymous	Exon 9 of 9	ENSP00000505197.1	A0A7P0T8Q3

Frequencies

GnomAD3 genomes

AF:

0.000368

AC:

AN:

152180

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000848

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000632

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000505

AC:

127

AN:

251472

AF XY:

0.000456

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00176

Gnomad NFE exome

AF:

0.000703

Gnomad OTH exome

AF:

0.000977

GnomAD4 exome

AF:

0.000626

AC:

915

AN:

1461888

Hom.:

Cov.:

AF XY:

0.000638

AC XY:

464

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.0000597

AC:

AN:

33480

American (AMR)

AF:

0.0000224

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:

0.00148

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000728

AC:

810

AN:

1112008

Other (OTH)

AF:

0.000381

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

Heterozygous variant carriers

111

166

222

277

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

104

130

<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:

0.000368

AC:

AN:

152298

Hom.:

Cov.:

AF XY:

0.000376

AC XY:

AN XY:

74462

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41554

American (AMR)

AF:

0.000131

AC:

AN:

15294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.000848

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000632

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

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:

0.000415

Hom.:

Bravo

AF:

0.000325

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000327

EpiControl

AF:

0.000652

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (2)

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.64

CADD

Benign

0.96

(source)

DANN

Benign

0.70

PhyloP100

-1.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=96/4

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

Computational scores

Splicing

Publications

Other links and lift over