TK2-related mitochondrial DNA maintenance defect

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TK2-related mitochondrial DNA maintenance defect, myopathic form

ORPHA:254875Disease

Also called TK2 deficiency · Thymidine kinase 2 deficiency · TK2d

What it is

A rare mitochondrial DNA depletion syndrome characterized by muscle weakness, and progressive, generalized hypotonia due to depletion of mtDNA in skeletal muscles. Clinical progression ranges from rapid and early fatal course due to respiratory failure, to slowly progressive myopathy over the course of childhood or even early adulthood.

Key facts

Prevalence
<1 / 1 000 000
Age of onset
Infancy, Neonatal
Inheritance
Autosomal recessive
Classified as
Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Genes reported in subtypes

TK2

Orphanet records this gene on 3 more specific entries under this disorder, not on this entry itself:

A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.

ICD-10 codes

G71.3filed under a broader ICD-10 category — shared with 27 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Benefit programs to look at

Programs whose eligibility touches the same ICD-10 categories. Eligibility is decided by the administering agency, never by this page.

Cross-references

MESH C563698MONDO 0012301OMIM 609560UMLS C3501891

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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