title: Disorders of nuclear-mitochondrial intergenomic signaling.
abstract: Depletion and multiple deletions of mitochondrial DNA (mtDNA) have been associated with a number of autosomal disorders classified as defects of nuclear-mitochondrial intergenomic signaling. The mendelian forms of progressive external ophthalmoplegia (PEO) are clinically and genetically heterogeneous disorders characterized by the accumulation of multiple deletions of mtDNA in postmitotic patient's tissues. Most of the autosomal dominant PEO (adPEO) families carry heterozygous mutations in either one of three genes: ANT1, Twinkle, and POLG1. Mutations in POLG1 can also cause autosomal recessive PEO (arPEO) and apparently sporadic cases. In addition, recessive POLG1 mutations are responsible for sensory-atactic neuropathy, dysarthria and ophthalmoplegia (SANDO), juvenile spino-cerebellar ataxia-epilepsy syndrome (SCAE) and Alpers-Huttenlocher hepatopathic poliodystrophy. Mutations in thymidine phosphorylase gene (TP) are linked to mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), an autosomal recessive disorder in which PEO is associated with gastrointestinal dysmotility and leukodystrophy. Finally, mitochondrial DNA depletion syndromes (MDS), defined by tissue-reduction in mtDNA copy number, have been linked to mutations in two genes involved in deoxyribonucleotide (dNTP) metabolism: thymidine kinase 2 (TK2) and deoxyguanosine kinase (DGUOK).
authors.affiliation: Unit of Molecular Neurogenetics, Pierfranco and Luisa Mariani Center for the Study of Children's Mitochondrial Disorders, National Neurological Institute, Milan, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Spinazzola
authors.forename: Massimo
authors.initials: M
authors.lastname: Zeviani
mesh_terms: D002467:Cell Nucleus / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D006801:Humans; D028361:Mitochondrial Diseases / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000235:genetics; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D013937:Thymidine Kinase / Q000235:genetics; D013939:Thymidine Phosphorylase / Q000235:genetics
chemical_list: D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D013939:Thymidine Phosphorylase; D017853:Phosphotransferases (Alcohol Group Acceptor); C019165:deoxyguanosine kinase; D013937:Thymidine Kinase