Genetic Variant TBC1D4:p.Leu278Val (chr13-75362274-G-C) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_014832.5(TBC1D4):c.832C>G(p.Leu278Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,508 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L278F) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

TBC1D4
NM_014832.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.243

Publications

0 publications found

Variant links:

Genes affected

TBC1D4 (HGNC:19165): (TBC1 domain family member 4) This gene is a member of the Tre-2/BUB2/CDC16 domain family. The protein encoded by this gene is a Rab-GTPase-activating protein, and contains two phopshotyrosine-binding domains (PTB1 and PTB2), a calmodulin-binding domain (CBD), a Rab-GTPase domain, and multiple AKT phosphomotifs. This protein is thought to play an important role in glucose homeostasis by regulating the insulin-dependent trafficking of the glucose transporter 4 (GLUT4), important for removing glucose from the bloodstream into skeletal muscle and fat tissues. Reduced expression of this gene results in an increase in GLUT4 levels at the plasma membrane, suggesting that this protein is important in intracellular retention of GLUT4 under basal conditions. When exposed to insulin, this protein is phosphorylated, dissociates from GLUT4 vesicles, resulting in increased GLUT4 at the cell surface, and enhanced glucose transport. Phosphorylation of this protein by AKT is required for proper translocation of GLUT4 to the cell surface. Individuals homozygous for a mutation in this gene are at higher risk for type 2 diabetes and have higher levels of circulating glucose and insulin levels after glucose ingestion. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Aug 2015]

TBC1D4 links:

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ACMG classification

Classification was made for transcript

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

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.052481294).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TBC1D4	NM_014832.5 link	c.832C>G	p.Leu278Val	missense_variant	Exon 2 of 21	ENST00000377636.8	NP_055647.2	O60343-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
TBC1D4	ENST00000377636.8 link	c.832C>G	p.Leu278Val	missense_variant	Exon 2 of 21	2	NM_014832.5	ENSP00000366863.3	O60343-1
TBC1D4	ENST00000431480.6 link	c.832C>G	p.Leu278Val	missense_variant	Exon 2 of 20	1		ENSP00000395986.2	O60343-3
TBC1D4	ENST00000377625.6 link	c.832C>G	p.Leu278Val	missense_variant	Exon 2 of 19	1		ENSP00000366852.2	O60343-2
TBC1D4	ENST00000648194.1 link	c.289C>G	p.Leu97Val	missense_variant	Exon 3 of 20			ENSP00000496983.1	A0A3B3IRT3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461508

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727082

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53132

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111958

Other (OTH)

AF:

0.00

AC:

AN:

60380

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.063

BayesDel_addAF

Benign

-0.38

BayesDel_noAF

Benign

-0.78

CADD

Benign

1.4

(source)

DANN

Benign

0.26

DEOGEN2

Benign

0.037

.;.;.;T

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.077

LIST_S2

Benign

0.64

T;T;T;T

M_CAP

Benign

0.0085

MetaRNN

Benign

0.052

T;T;T;T

MetaSVM

Benign

-0.90

MutationAssessor

Benign

0.0

.;N;N;N

PhyloP100

-0.24

PrimateAI

Benign

0.25

PROVEAN

Benign

-0.17

.;N;N;N

REVEL

Benign

0.016

Sift

Benign

0.54

.;T;T;T

Sift4G

Benign

0.32

.;T;T;T

Polyphen

0.0010, 0.0

.;B;B;B

Vest4

0.034, 0.044

MutPred

0.39

.;Gain of catalytic residue at L280 (P = 0);Gain of catalytic residue at L280 (P = 0);Gain of catalytic residue at L280 (P = 0);

MVP

0.32

MPC

0.34

ClinPred

0.027

GERP RS

1.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.029

gMVP

0.094

Mutation Taster

=99/1

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

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over