title: Trinucleotide repeat expansion of TATA-binding protein gene associated with Parkinson's disease: A Thai multicenter study.
abstract: Spinocerebellar ataxia type 17 (SCA17) is an inherited cerebellar degeneration associated with trinucleotide repeat expansions in the TATA-binding protein gene (TBP). Low-range expansions of TBP have recently been described in association with Parkinson's disease (PD). However, these low-range expansion alleles were also observed in healthy individuals. Prior distinct findings may result from reduced penetrance or age-dependent susceptibility, which may influence phenotypic expression.
  
  
  
  A case-control study of 456 PD patients and 374 control subjects was conducted. Data and blood samples were collected during 2008-2013. Control subjects were individuals over 65 years old without parkinsonism. Sizes of TBP trinucleotide repeats were analyzed. All available carriers of the TBP repeat of ≥40 repeats were re-examined.
  
  
  
  A high prevalence of carriers of TBP repeat expansion ≥41 developed PD, mainly at an advanced age. Half of these carriers had onset after 70 years of age (range 34-84). Seven participants carried expansion alleles of ≥42, and all had PD. Fourteen participants (six patients and eight controls) carried a heterozygous 41-repeat allele. At the current mean age of 79 years and mean follow-up period of 4 years, three out of the eight control carriers of the 41-repeat allele developed PD, while none of the thirteen asymptomatic carriers of the 40-repeat allele did.
  
  
  
  A high prevalence of PD was observed in carriers of low-range expansions of TBP (41-45 repeats), especially in elderly. This finding suggests that cut-off value for pathological TBP repeat expansion appear to be 41.
authors.affiliation: Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Lulin
authors.initials: L
authors.lastname: Choubtum
authors.affiliation: Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Pirada
authors.initials: P
authors.lastname: Witoonpanich
authors.affiliation: Division of Neurology, Department of Medicine, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand.
authors.forename: Kongkiat
authors.initials: K
authors.lastname: Kulkantrakorn
authors.affiliation: Department of Neurology, Prasat Neurological Institute, Bangkok, Thailand.
authors.forename: Suchat
authors.initials: S
authors.lastname: Hanchaiphiboolkul
authors.affiliation: Division of Neurology, Department of Medicine, Bhumibol Adulyadej Hospital, Bangkok, Thailand.
authors.forename: Sunsanee
authors.initials: S
authors.lastname: Pongpakdee
authors.affiliation: Division of Neurology, Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Somsak
authors.initials: S
authors.lastname: Tiamkao
authors.affiliation: Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. Electronic address: teeratorn.pul@mahidol.ac.th.
authors.forename: Teeratorn
authors.initials: T
authors.lastname: Pulkes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000235:genetics*; D035181:TATA-Box Binding Protein / Q000235:genetics*; D013785:Thailand; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
chemical_list: D035181:TATA-Box Binding Protein
keywords: Parkinson's disease; Spinocerebellar ataxia type 17; TATA box-binding protein gene; TBP; Trinucleotide repeat expansion