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TK2

Synonyms
MTDPS2, MTTK, PEOB3, SCA31, TK2-EXT
External resources
Summary
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.

Variant counts

The variants found in rare patients tested by 3billion are classified and counted according to ACMG guidelines. The variants with over 5% variant frequency in population genome databases ( gnomAD, dbSNP, etc) are excluded.

Pathogenic
7
Likely pathogenic
7
VUS
2,153
Likely benign
3,162
Benign
98

Patient phenotypes

Proportions of phenotypes among 14 patients carrying pathogenic or likely pathogenic variants on TK2 gene are displayed below.

Phenotype class
Patients in 3billion (%)
Abnormality of the musculoskeletal system
50%
Abnormality of the nervous system
42.9%
Growth abnormality
35.7%
Abnormality of head or neck
28.6%
Abnormality of limbs
28.6%
Abnormality of the digestive system
28.6%
Abnormality of the cardiovascular system
21.4%
Abnormality of the eye
21.4%
Abnormality of the genitourinary system
21.4%
Abnormality of the integument
21.4%
Abnormality of the ear
14.3%
Constitutional symptom
14.3%
Abnormality of prenatal development or birth
7.1%
Abnormality of the endocrine system
7.1%
Abnormal cellular phenotype
0%
Abnormality of blood and blood-forming tissues
0%
Abnormality of metabolism homeostasis
0%
Abnormality of the breast
0%
Abnormality of the immune system
0%
Abnormality of the respiratory system
0%
Abnormality of the thoracic cavity
0%
Abnormality of the voice
0%
Neoplasm
0%

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