chr16-66529055-G-A

Position:

chr16-66529055-G-A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1PM2PM5PP5_Very_Strong

The NM_004614.5(TK2):c.388C>T(p.Arg130Trp) variant causes a missense change. The variant allele was found at a frequency of 0.0000347 in 1,613,766 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R130Q) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000031 ( 0 hom. )

Consequence

TK2
NM_004614.5 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4O:1

Conservation

PhyloP100: 3.76

Variant links:

Genes affected

TK2 (HGNC:11831): (thymidine kinase 2) This gene encodes a deoxyribonucleoside kinase that specifically phosphorylates thymidine, deoxycytidine, and deoxyuridine. The encoded enzyme localizes to the mitochondria and is required for mitochondrial DNA synthesis. Mutations in this gene are associated with a myopathic form of mitochondrial DNA depletion syndrome. Alternate splicing results in multiple transcript variants encoding distinct isoforms, some of which lack transit peptide, so are not localized to mitochondria. [provided by RefSeq, Dec 2012]

TK2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 14 ACMG points.

PM1

In a chain Thymidine kinase 2, mitochondrial (size 231) in uniprot entity KITM_HUMAN there are 9 pathogenic changes around while only 1 benign (90%) in NM_004614.5

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr16-66529054-C-T is described in Lovd as [Pathogenic].

PP5

Variant 16-66529055-G-A is Pathogenic according to our data. Variant chr16-66529055-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 38988.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TK2	NM_004614.5 linkuse as main transcript	c.388C>T	p.Arg130Trp	missense_variant	6/10	ENST00000544898.6	NP_004605.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TK2	ENST00000544898.6 linkuse as main transcript	c.388C>T	p.Arg130Trp	missense_variant	6/10	1	NM_004614.5	ENSP00000440898	P1	O00142-1

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152106

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.000755

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000756

AC:

AN:

251236

Hom.:

AF XY:

0.0000663

AC XY:

AN XY:

135824

show subpopulations

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 SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.000745

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000308

AC:

AN:

1461660

Hom.:

Cov.:

AF XY:

0.0000330

AC XY:

AN XY:

727134

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.000638

Gnomad4 NFE exome

AF:

0.00000630

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152106

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74300

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.000755

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000250

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000659

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 16, 2024	Published functional studies found this variant is associated with significantly reduced enzyme activity (PMID: 20083405); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Also known as p.(R172W); This variant is associated with the following publications: (PMID: 20083405, 18819985, no PMID, 31060578, 29602790, 23230576, 32827528, 34426522, 31589614, 34973561) -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 20, 2023	This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 130 of the TK2 protein (p.Arg130Trp). This variant is present in population databases (rs281865493, gnomAD 0.08%). This missense change has been observed in individual(s) with mitochondrial DNA depletion syndrome (PMID: 20083405, 29602790). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 38988). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TK2 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects TK2 function (PMID: 20083405). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 23, 2020	- -

Mitochondrial DNA depletion syndrome, myopathic form

Pathogenic:1Other:1

not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Apr 04, 2024	- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.47

BayesDel_addAF

Pathogenic

0.36

BayesDel_noAF

Pathogenic

0.47

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.96

D;.;D;.;.;.;.;D;.;.;.;D;D

Eigen

Uncertain

0.66

Eigen_PC

Uncertain

0.60

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

0.98

D;D;.;D;.;D;D;D;.;D;D;D;D

M_CAP

Uncertain

0.27

MetaRNN

Uncertain

0.67

D;D;D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.86

MutationAssessor

Pathogenic

3.1

M;.;M;.;.;.;.;.;.;.;.;.;.

MutationTaster

Benign

1.0

D;D;D;D;D;D;D;D;D;D

PrimateAI

Uncertain

0.54

PROVEAN

Pathogenic

-6.6

.;.;.;.;D;D;D;D;D;.;.;.;.

REVEL

Pathogenic

0.83

Sift

Pathogenic

0.0

.;.;.;.;D;D;D;D;D;.;.;.;.

Sift4G

Uncertain

0.0030

D;D;D;D;D;D;D;D;D;D;D;.;.

Polyphen

1.0

D;.;D;.;.;D;.;.;.;.;.;.;.

Vest4

0.93

MutPred

0.58

.;.;.;Loss of disorder (P = 0.005);.;.;.;.;.;.;.;.;.;

MVP

1.0

MPC

1.2

ClinPred

0.87

GERP RS

4.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.92

gMVP

0.82

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over