title: Associations between TOMM40 Poly-T Repeat Variants and Dementia in Cases with Parkinsonism.
abstract: BACKGROUND
  Mitochondrial dysfunction has been implicated in the pathophysiology of Parkinson's disease (PD)-related pathologies.
  
  
  OBJECTIVE
  To investigate the role of the Translocase of the Outer Mitochondrial Membrane 40 homolog (TOMM40) variants in PD without dementia (PDND), PD with dementia (PDD) and in Dementia with Lewy bodies (DLB).
  
  
  METHODS
  248 individuals, including 92 PDND, 55 PDD, and 101 DLB, were included. The rs10524523 locus in the TOMM40 gene (TOMM40 poly-T repeat) is characterized by a variable number of T residues that were classified into three groups based on length; short (S), long (L), and very long (VL). We tested log-additive genetic model of association with dementia and adjusted for age, sex, and APOEɛ4 carrier status. We analyzed cerebrospinal fluid (CSF) levels of Aβ42 and Tau, biomarkers related to Alzheimer's disease (AD).
  
  
  RESULTS
  PDD/DBL status and abnormal CSF AD biomarkers (Aβ42 and Aβ42/Tau ratio) were both associated with the APOEɛ4 allele (p <  0.014) and the L allele of TOMM40 poly-T repeat (p <  0.008). The VL allele was less frequently observed in the PDD/DLB group (p = 0.013). In APOE-ɛ4 adjusted analyses, the relationships between the L and VL alleles and dementia status as well as CSF AD biomarkers were not significant. When adjusting for APOE-ɛ4, however, there were associations between S carrier status and PDD/DLB (p = 0.019) and abnormal CSF levels of Aβ42/Tau ratio (p = 0.037) although these were not significant after adjustment for multiple comparisons.
  
  
  CONCLUSIONS
  Our results do not support the notion that TOMM40 poly-T repeat variants have independent effects on PDD and DLB pathology. This relationship seems to be driven by APOE-ɛ4.
authors.affiliation: Division of Psychiatry, Department of Clinical Sciences, Lund University, Lund, Sweden.|Psychiatry Skåne, Lund, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lindqvist
authors.affiliation: Neuroepidemiology and Ageing Research, School of Public Health, Imperial College London, UK.
authors.forename: Inga
authors.initials: I
authors.lastname: Prokopenko
authors.affiliation: Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.|Memory Clinic, Skåne University Hospital, Lund, Sweden.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Londos
authors.affiliation: Neuroepidemiology and Ageing Research, School of Public Health, Imperial College London, UK.
authors.forename: Lefkos
authors.initials: L
authors.lastname: Middleton
authors.affiliation: Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden.|Memory Clinic, Skåne University Hospital, Lund, Sweden.
authors.forename: Oskar
authors.initials: O
authors.lastname: Hansson
mesh_terms: D000368:Aged; D001057:Apolipoproteins E / Q000235:genetics; D015415:Biomarkers / Q000134:cerebrospinal fluid; D003704:Dementia / Q000235:genetics* / Q000473:pathology; D005260:Female; D005838:Genotype; D006801:Humans; D020961:Lewy Body Disease / Q000235:genetics* / Q000473:pathology; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D020734:Parkinsonian Disorders / Q000235:genetics* / Q000473:pathology; D011071:Poly T / Q000235:genetics*
chemical_list: C000612345:ApoE protein, human; D001057:Apolipoproteins E; D015415:Biomarkers; D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; C400783:TOMM40 protein, human; D011071:Poly T
keywords: APOE; DLB; PDD; Parkinson’s disease; TOMM40