title: POLG-Associated Ataxia Presenting as a Fragile X Tremor/Ataxia Phenocopy Syndrome.
abstract: Hyperintensities in the middle cerebellar peduncles (MCP), known as the MCP sign, and progressive late-onset ataxia constitute major characteristics of the fragile X tremor/ataxia syndrome (FXTAS). Here, we describe a 60-year-old male affected by ataxia due to biallelic mutations in the mitochondrial polymerase gamma (POLG) gene in which hyperintensities of the middle cerebellar peduncles (MCP) were found. The initial suspicion of FXTAS was however ruled out by a normal CGG expansion size in the FMR1 gene. We discuss the features of late-onset POLG-A as a phenocopy of FXTAS.
authors.affiliation: Department of Neurology, Karolinska University Hospital, Stockholm, Sweden. martin.paucar-arce@karolinska.se.|Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. martin.paucar-arce@karolinska.se.
authors.forename: Martin
authors.initials: M
authors.lastname: Paucar
authors.affiliation: Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.|Center for Inherited Metabolic Disorders, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Engvall
authors.affiliation: Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Lisa
authors.initials: L
authors.lastname: Gordon
authors.affiliation: Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.|Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Emma
authors.initials: E
authors.lastname: Tham
authors.affiliation: Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, Tübingen, Germany.|German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany.
authors.forename: Matthis
authors.initials: M
authors.lastname: Synofzik
authors.affiliation: Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.|Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Svenningsson
mesh_terms: D001259:Ataxia / Q000175:diagnosis* / Q000235:genetics*; D001921:Brain / Q000000981:diagnostic imaging; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D003937:Diagnosis, Differential; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; D051860:Fragile X Messenger Ribonucleoprotein 1; C497683:FMR1 protein, human; C413027:POLG protein, human
keywords: FXTAS; MCP sign; POLG