The CIBERER group led by Dr. Ramon Martí, head of the Neuromuscular and Mitochondrial Pathology research group at the Vall d'Hebron Research Institute (VHIR) and the CIBEREHD group led by Dr. Marçal Pastor-Anglada at the University of Barcelona have obtained 296,375 euros in funding from La Marató de TV3 for a project of search for deoxyribonucleoside therapies for various mitochondrial diseases.In a previous project coordinated by Dr. Martí's team, deoxyribonucleosides were administered to patients with a mitochondrial disease, TK2 deficiency, under a compassionate use program. This therapy, which improved motor functions and increased survival of those affected, is now in the clinical trial phase.With the new project, financed in the 2019 edition of La Marató dedicated to the minority diseases and whose agreement has just been formalized, the research groups of the CIBERER (Center for Networked Biomedical Research on Rare Diseases) and the CIBEREHD (focused on Hepatic and Digestive Diseases) will study the possible extension of the therapy based on the administration of deoxyribonucleosides to other disorders characterized by problems in the replication of mitochondrial DNA as a consequence of mutations in POLG (DNA polymerase gamma) and other genes.To do this, they will use different animal models, both developed within the framework of the same project and provided by other collaborating researchers, and will specifically delve into the role that nucleoside transporters play in the therapeutic mechanisms of this treatment.Pathologies caused by defects in the maintenance of mitochondrial DNA constitute an important group of mitochondrial diseases. These are diseases that are inherited in an autosomal recessive or dominant manner and affect proteins directly or indirectly involved in the synthesis of mitochondrial DNA. Mutations in these genes lead to alterations in the quantity or integrity of the mitochondrial DNA molecules, producing occasional mutations, multiple deletions or a loss of DNA molecules below the physiological threshold (depletion), which translates into an energy deficiency in the affected tissues.The clinical spectrum of these diseases is very broad, ranging from severe multisystemic affections in childhood to mild myopathies in adulthood. In any case, the therapeutic options are mainly limited to symptomatic or palliative treatments. It is a group of diseases with very heterogeneous genetics, which can be due to mutations in a wide variety of genes.