title: Number of CAG repeats in POLG1 and its association with Parkinson disease in the Norwegian population.
abstract: The number of CAG repeats in the mitochondrial DNA-polymerase gamma (POLG1) gene has been associated with Parkinson disease (PD) in some populations. We sequenced the CAG tract of POLG1 in 191 Norwegian patients with PD and an equal number of controls and found an association between non-10 or 11 CAG repeats and PD in our population. While our results were significant, this trend was not maintained following correction for multiple testing. We also performed a meta-analysis of all published studies including our own that shows PD is associated with the number of CAG repeats in POLG1. The meta-analysis reveals that the rare allelic variation encompassed by non-10 CAG repeats associates significantly with PD (p=0.0017). Whether this reflects a direct influence of POLG on the pathogenesis of PD or linkage disequilibrium between POLG1 alleles and nearby, disease-influencing genetic variants remains unknown.
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: Novin
authors.initials: N
authors.lastname: Balafkan
authors.forename: Charalampos
authors.initials: C
authors.lastname: Tzoulis
authors.forename: Bernd
authors.initials: B
authors.lastname: Müller
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Haugarvoll
authors.forename: Ole-Bjørn
authors.initials: OB
authors.lastname: Tysnes
authors.forename: Jan Petter
authors.initials: JP
authors.lastname: Larsen
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Bindoff
mesh_terms: D000074002:DNA Polymerase gamma; D004272:DNA, Mitochondrial / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D009664:Norway; D010300:Parkinson Disease / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004272:DNA, Mitochondrial; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C413027:POLG protein, human