13-75359852-G-T

Variant names:

• chr13-75359852-G-T
• rs587777260
• NM_014832.5:c.1087C>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_014832.5(TBC1D4):​c.1087C>A​(p.Arg363Arg) variant causes a synonymous change. The variant allele was found at a frequency of 0.000013 in 1,612,948 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000014 (0 hom.)
• Consequence: TBC1D4 NM_014832.5 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.60
• Publications: 12 publications found

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]

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.31).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TBC1D4	NM_014832.5	c.1087C>A	p.Arg363Arg	synonymous_variant	Exon 3 of 21	ENST00000377636.8	NP_055647.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TBC1D4	ENST00000377636.8	c.1087C>A	p.Arg363Arg	synonymous_variant	Exon 3 of 21	2	NM_014832.5	ENSP00000366863.3
TBC1D4	ENST00000431480.6	c.1087C>A	p.Arg363Arg	synonymous_variant	Exon 3 of 20	1		ENSP00000395986.2
TBC1D4	ENST00000377625.6	c.1087C>A	p.Arg363Arg	synonymous_variant	Exon 3 of 19	1		ENSP00000366852.2
TBC1D4	ENST00000648194.1	c.544C>A	p.Arg182Arg	synonymous_variant	Exon 4 of 20			ENSP00000496983.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151996 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249320 AF XY: 0.00000739

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000884

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000137 AC: 20 AN: 1460952 Hom.: 0 Cov.: 30 AF XY: 0.0000151 AC XY: 11 AN XY: 726858

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33450

American (AMR) AF: 0.00 AC: 0 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39556

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86216

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.0000162 AC: 18 AN: 1111384

Other (OTH) AF: 0.0000166 AC: 1 AN: 60362

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000000000908162), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151996 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74230

African (AFR) AF: 0.0000242 AC: 1 AN: 41396

American (AMR) AF: 0.00 AC: 0 AN: 15266

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

South Asian (SAS) AF: 0.00 AC: 0 AN: 4806

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10558

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67988

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000227

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.31
CADD	Benign	12
DANN	Benign	0.72
PhyloP100		5.6

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs587777260; hg19: chr13-75933988;