rs529176585

chr16-66513721-TCTTA-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP6 BS1

The NM_004614.5(TK2):c.699+6_699+9del variant causes a splice donor region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000118 in 1,612,932 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00021 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (1 hom.)
• Consequence: TK2 NM_004614.5 splice_donor_region, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 2.28

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]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 16-66513721-TCTTA-T is Benign according to our data. Variant chr16-66513721-TCTTA-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 225491.We mark this variant Likely_benign, oryginal submissions are: {Benign=1, Uncertain_significance=1}.
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.000211 (32/151954) while in subpopulation EAS AF= 0.00581 (30/5164). AF 95% confidence interval is 0.00418. There are 0 homozygotes in gnomad4. There are 18 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TK2	NM_004614.5	c.699+6_699+9del		splice_donor_region_variant, intron_variant		ENST00000544898.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TK2	ENST00000544898.6	c.699+6_699+9del		splice_donor_region_variant, intron_variant		1	NM_004614.5	P1

Frequencies

GnomAD3 genomes AF: 0.000211 AC: 32 AN: 151836 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00580

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000613 AC: 154 AN: 251254 Hom.: 1 AF XY: 0.000633 AC XY: 86 AN XY: 135806

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00821

Gnomad SAS exome AF: 0.0000980

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000109 AC: 159 AN: 1460978 Hom.: 1 AF XY: 0.000117 AC XY: 85 AN XY: 726850

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00365

Gnomad4 SAS exome AF: 0.0000580

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.000133

GnomAD4 genome AF: 0.000211 AC: 32 AN: 151954 Hom.: 0 Cov.: 32 AF XY: 0.000242 AC XY: 18 AN XY: 74260

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00581

Gnomad4 SAS AF: 0.000208

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.000325

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Mitochondrial DNA depletion syndrome, myopathic form Uncertain:1

Uncertain significance, criteria provided, single submitter

reference population

Soonchunhyang University Bucheon Hospital, Soonchunhyang University Medical Center

Mar 18, 2016

- -

not provided Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jan 25, 2024

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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

Other links and lift over

dbSNP: rs529176585; hg19: chr16-66547624;