Genetic Variant TKT:p.Arg550His (chr3-53226803-C-T) – ACMG Classification: Likely_benign (-1 pts)

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_001064.4(TKT):c.1649G>A(p.Arg550His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000195 in 1,614,014 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 Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00021 ( 0 hom. )

Consequence

TKT
NM_001064.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.80

Publications

3 publications found

Variant links:

Genes affected

TKT (HGNC:11834): (transketolase) This gene encodes a thiamine-dependent enzyme which plays a role in the channeling of excess sugar phosphates to glycolysis in the pentose phosphate pathway. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Apr 2012]

TKT Gene-Disease associations (from GenCC):

transketolase deficiency
Inheritance: AR Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)

TKT links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.36473453).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TKT	NM_001064.4 link	c.1649G>A	p.Arg550His	missense_variant	Exon 13 of 14	ENST00000462138.6	NP_001055.1	P29401-1V9HWD9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TKT	ENST00000462138.6 link	c.1649G>A	p.Arg550His	missense_variant	Exon 13 of 14	1	NM_001064.4	ENSP00000417773.1		P29401-1

Frequencies

GnomAD3 genomes

AF:

0.0000788

AC:

AN:

152204

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.000132

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000159

AC:

AN:

251176

AF XY:

0.000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000194

Gnomad OTH exome

AF:

0.000653

GnomAD4 exome

AF:

0.000207

AC:

302

AN:

1461810

Hom.:

Cov.:

AF XY:

0.000205

AC XY:

149

AN XY:

727208

show subpopulations

African (AFR)

AF:

0.000119

AC:

AN:

33474

American (AMR)

AF:

0.0000895

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.000378

AC:

AN:

39698

South Asian (SAS)

AF:

0.000301

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.00191

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.000203

AC:

226

AN:

1111970

Other (OTH)

AF:

0.000265

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.473

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000788

AC:

AN:

152204

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74360

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00316

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000132

AC:

AN:

68044

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.517

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.000165

Hom.:

Bravo

AF:

0.0000869

TwinsUK

AF:

0.000539

AC:

ALSPAC

AF:

0.00

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000173

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000178

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Mar 03, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1649G>A (p.R550H) alteration is located in exon 13 (coding exon 13) of the TKT gene. This alteration results from a G to A substitution at nucleotide position 1649, causing the arginine (R) at amino acid position 550 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.090

BayesDel_addAF

Benign

-0.099

BayesDel_noAF

Uncertain

-0.070

CADD

Uncertain

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.83

D;D;.;T

Eigen

Uncertain

0.48

Eigen_PC

Uncertain

0.43

FATHMM_MKL

Uncertain

0.86

LIST_S2

Benign

0.81

.;T;T;T

M_CAP

Uncertain

0.22

MetaRNN

Benign

0.36

T;T;T;T

MetaSVM

Pathogenic

0.81

MutationAssessor

Uncertain

2.4

M;M;.;.

PhyloP100

1.8

PrimateAI

Benign

0.31

PROVEAN

Uncertain

-3.2

D;D;D;.

REVEL

Uncertain

0.50

Sift

Benign

0.10

T;T;T;.

Sift4G

Benign

0.078

T;T;T;T

Polyphen

0.94

P;P;.;.

Vest4

0.29

MVP

0.91

MPC

1.1

ClinPred

0.24

GERP RS

4.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.20

gMVP

0.68

Mutation Taster

=49/51

disease causing

(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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3-53226803-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over