NM_004614.5:c.547C>G

Variant names:

• chr16-66517207-G-C
• rs137886900
• NM_004614.5:c.547C>G

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_004614.5(TK2):​c.547C>G​(p.Arg183Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,794 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R183Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: TK2 NM_004614.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 5.18
• Publications: 19 publications found

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

ENSG00000260851 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain 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 chr16-66517207-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 38992.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.908
• PP5: Variant 16-66517207-G-C is Pathogenic according to our data. Variant chr16-66517207-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 38991.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TK2	NM_004614.5	MANE Select	c.547C>G	p.Arg183Gly	missense	Exon 8 of 10	NP_004605.4
	TK2	NM_001172645.2		c.493C>G	p.Arg165Gly	missense	Exon 7 of 9	NP_001166116.1	O00142-4
	TK2	NM_001172644.2		c.472C>G	p.Arg158Gly	missense	Exon 7 of 9	NP_001166115.1	O00142-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TK2	ENST00000544898.6	TSL:1 MANE Select	c.547C>G	p.Arg183Gly	missense	Exon 8 of 10	ENSP00000440898.2	O00142-1
	TK2	ENST00000451102.7	TSL:1	c.454C>G	p.Arg152Gly	missense	Exon 8 of 10	ENSP00000414334.4	O00142-2
	TK2	ENST00000527284.6	TSL:1	c.490C>G	p.Arg164Gly	missense	Exon 8 of 9	ENSP00000435312.2	A0A7P0PE46

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251488 AF XY: 0.00000736

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461794 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727206

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000630 AC: 7 AN: 1111920

Other (OTH) AF: 0.0000166 AC: 1 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000247 AC: 3

EpiCase AF: 0.000218

EpiControl AF: 0.000119

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	Mitochondrial disease (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.52
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		5.2
PrimateAI	Benign	0.27	T
PROVEAN	Pathogenic	-5.3	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0020	D
Polyphen		0.99	D
Vest4		0.84
MutPred		0.70		Loss of glycosylation at P228 (P = 0.0836)
MVP		0.99
MPC		1.1
ClinPred		0.98	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.95
gMVP		0.63
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: rs137886900; hg19: chr16-66551110;