The DGUOK gene is located chromosome on 2p13.1. It provides instruction for making a mitochondrial enzyme of 277 amino acids called deoxyguanosine kinase. This enzyme is involved in producing and maintaining the building blocks of mitochondrial DNA. Specifically, it is responsible for phosphorylation of purine deoxyribonucleosides in the mitochondrial matrix.
Defects in this enzyme are the cause of Mitochondrial DNA depletion syndrome 3 (MTDPS3), a disorder characterized by onset in infancy of progressive liver failure, hypoglycemia, increased lactate in body fluids, and neurologic abnormalities including hypotonia, encephalopathy, and peripheral neuropathy.