dbSNP rs281865495: TK2:p.Thr188Ala (chr16-66517192-T-C) – ACMG Classification: Pathogenic (11 pts)

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 12P and 1B. PM1PM2PP5_Very_StrongBP4

The NM_004614.5(TK2):c.562A>G(p.Thr188Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,614,038 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 Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

TK2
NM_004614.5 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 3.26

Publications

6 publications found

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 Gene-Disease associations (from GenCC):

mitochondrial disease
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
mitochondrial DNA depletion syndrome, myopathic form
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Orphanet, Labcorp Genetics (formerly Invitae), G2P
autosomal recessive progressive external ophthalmoplegia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

TK2 links:

ENSG00000260851 (HGNC:):

ENSG00000260851 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1

In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_004614.5

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 16-66517192-T-C is Pathogenic according to our data. Variant chr16-66517192-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 38993.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP4

Computational evidence support a benign effect (MetaRNN=0.3629625). . Strength limited to SUPPORTING due to the PP5.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004614.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TK2	NM_004614.5	MANE Select	c.562A>G	p.Thr188Ala	missense	Exon 8 of 10	NP_004605.4
TK2	NM_001172645.2		c.508A>G	p.Thr170Ala	missense	Exon 7 of 9	NP_001166116.1	O00142-4
TK2	NM_001172644.2		c.487A>G	p.Thr163Ala	missense	Exon 7 of 9	NP_001166115.1	O00142-3

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TK2	ENST00000544898.6	TSL:1 MANE Select	c.562A>G	p.Thr188Ala	missense	Exon 8 of 10	ENSP00000440898.2	O00142-1
TK2	ENST00000451102.7	TSL:1	c.469A>G	p.Thr157Ala	missense	Exon 8 of 10	ENSP00000414334.4	O00142-2
TK2	ENST00000527284.6	TSL:1	c.505A>G	p.Thr169Ala	missense	Exon 8 of 9	ENSP00000435312.2	A0A7P0PE46

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152170

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:

0.000188

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000795

AC:

AN:

251494

AF XY:

0.00000736

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461868

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727234

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

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:

86256

European-Finnish (FIN)

AF:

0.000112

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111990

Other (OTH)

AF:

0.0000497

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.545

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152170

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74326

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.000188

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000363

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

ClinVar submissions

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Mitochondrial disease (1)

not provided (1)

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 3 (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Pathogenic

0.22

BayesDel_noAF

Uncertain

0.080

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.77

Eigen

Benign

-0.037

Eigen_PC

Benign

0.13

FATHMM_MKL

Benign

0.58

LIST_S2

Uncertain

0.87

M_CAP

Benign

0.055

MetaRNN

Benign

0.36

MetaSVM

Uncertain

0.31

MutationAssessor

Uncertain

2.6

PhyloP100

3.3

PrimateAI

Benign

0.30

PROVEAN

Benign

-2.1

REVEL

Uncertain

0.58

Sift

Benign

0.11

Sift4G

Benign

0.23

Polyphen

0.020

Vest4

0.68

MutPred

0.46

Loss of phosphorylation at T230 (P = 0.0493)

MVP

0.95

MPC

0.38

ClinPred

0.79

GERP RS

4.5

Varity_R

0.10

gMVP

0.40

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over