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DGUOK gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

DGUOK gene

The DGUOK gene provides instructions for making the enzyme deoxyguanosine kinase, which is essential for maintaining mitochondrial DNA and cellular energy production.

Normal Function

The DGUOK gene provides instructions for making the enzyme deoxyguanosine kinase. This enzyme plays a critical role in mitochondria, which are the energy-producing centers inside the cell. Mitochondria each contain their own DNA, known as mitochondrial DNA (mtDNA), that is essential for their normal function. Deoxyguanosine kinase is involved in producing and maintaining the building blocks (nucleosides) that make up mtDNA.

Health Conditions Related to Genetic Changes

Deoxyguanosine kinase deficiency

Many variants (also called mutations) in the DGUOK gene have been identified in people with deoxyguanosine kinase deficiency, an inherited disorder that can disrupt the normal function of the liver, muscles, and brain. Some of these variants change single protein building blocks (amino acids) in the deoxyguanosine kinase enzyme. Other variants cause cells to produce an abnormally short, nonfunctional version of the enzyme or change the way in which the gene is processed.

Variants in the DGUOK gene that cause deoxyguanosine kinase deficiency reduce or eliminate the activity of the deoxyguanosine kinase enzyme. Reduced enzyme activity leads to problems with the production and maintenance of mtDNA. A decrease in the amount of mtDNA (known as mtDNA depletion) impairs mitochondrial function in many of the body's cells and tissues. These problems lead to the brain, liver, and muscle dysfunction associated with deoxyguanosine kinase deficiency.

Progressive external ophthalmoplegia

MedlinePlus Genetics provides information about Progressive external ophthalmoplegia.

Other Names for This Gene

  • deoxyguanosine kinase, mitochondrial
  • DGK
  • dGK

Frequently Asked Questions

The most common early presentation is the infantile hepatocerebral form, which typically emerges within the first few weeks to months of life. Parents and pediatricians often notice persistent jaundice, poor feeding, failure to thrive, abdominal distension from an enlarged liver (hepatomegaly), and recurrent hypoglycemia. Neurological signs quickly follow, including severe low muscle tone (hypotonia), rotary nystagmus (involuntary eye movements), psychomotor regression, and progressive lethargy. Elevated serum ferritin, transaminases, and lactic acid are typical early laboratory findings.
Liver transplantation remains controversial and must be evaluated on a case-by-case basis. While transplantation can correct life-threatening hepatic failure in isolated or predominantly liver-limited presentations, it does not stop or reverse mitochondrial DNA depletion in the central nervous system. Infants with significant preexisting neurological abnormalities generally continue to experience progressive, irreversible neurodegeneration after transplantation. Consequently, rigorous multi-organ neurological and metabolic staging is required before determining transplant eligibility.
dult-onset DGUOK-related disease typically presents with an entirely different clinical picture, most often characterized by progressive external ophthalmoplegia (PEO). Instead of acute infantile liver failure, adults experience drooping eyelids (ptosis), progressive weakness of the extraocular muscles, exercise intolerance, and proximal muscle weakness. Adult manifestations can follow an autosomal dominant or recessive inheritance pattern and generally run a much slower, more indolent clinical course than the severe infantile form.
Diagnosis relies on a combination of biochemical screening and molecular genetic testing. Laboratory workups often show elevated serum lactic acid, liver dysfunction with elevated alpha-fetoprotein and ferritin, and low mitochondrial DNA copy numbers on liver or muscle tissue biopsy. Definitive confirmation is achieved through molecular genetic testing, such as targeted single-gene sequencing, a multi-gene mitochondrial panel, or whole exome sequencing, identifying pathogenic variants in both copies of the DGUOK gene.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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