title: Genes and Pathways Involved in Adult Onset Disorders Featuring Muscle Mitochondrial DNA Instability.
abstract: Replication and maintenance of mtDNA entirely relies on a set of proteins encoded by the nuclear genome, which include members of the core replicative machinery, proteins involved in the homeostasis of mitochondrial dNTPs pools or deputed to the control of mitochondrial dynamics and morphology. Mutations in their coding genes have been observed in familial and sporadic forms of pediatric and adult-onset clinical phenotypes featuring mtDNA instability. The list of defects involved in these disorders has recently expanded, including mutations in the exo-/endo-nuclease flap-processing proteins MGME1 and DNA2, supporting the notion that an enzymatic DNA repair system actively takes place in mitochondria. The results obtained in the last few years acknowledge the contribution of next-generation sequencing methods in the identification of new disease loci in small groups of patients and even single probands. Although heterogeneous, these genes can be conveniently classified according to the pathway to which they belong. The definition of the molecular and biochemical features of these pathways might be helpful for fundamental knowledge of these disorders, to accelerate genetic diagnosis of patients and the development of rational therapies. In this review, we discuss the molecular findings disclosed in adult patients with muscle pathology hallmarked by mtDNA instability.
authors.affiliation: Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy. naghia.ahmed89@gmail.com.
authors.forename: Naghia
authors.initials: N
authors.lastname: Ahmed
authors.affiliation: Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy. dario.ronchi@gmail.com.
authors.forename: Dario
authors.initials: D
authors.lastname: Ronchi
authors.affiliation: Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy. giacomo.comi@unimi.it.
authors.forename: Giacomo Pietro
authors.initials: GP
authors.lastname: Comi
mesh_terms: D000328:Adult; D004272:DNA, Mitochondrial / Q000235:genetics*; D042822:Genomic Instability; D006801:Humans; D008931:Mitochondria, Muscle / Q000235:genetics* / Q000473:pathology*; D028361:Mitochondrial Diseases / Q000235:genetics* / Q000473:pathology*; D009132:Muscles / Q000378:metabolism / Q000473:pathology; D009154:Mutation
chemical_list: D004272:DNA, Mitochondrial
keywords: adult mitochondrial disorders; mitochondrial myopathy; mtDNA maintenance; multiple mtDNA deletions; progressive external ophthalmoplegia