Absence of C9ORF72 expanded or intermediate repeats in autopsy-confirmed Parkinson's disease

Mov Disord. 2014 May;29(6):827-30. doi: 10.1002/mds.25838. Epub 2014 Feb 26.


Background: We have reported that intermediate repeat lengths of the C9ORF72 repeat are a risk factor for Parkinson's disease (PD) in a clinically diagnosed data set. Because 10% to 25% of clinically diagnosed PD have different diagnoses upon autopsy, we hypothesized that this may reflect phenotypic heterogeneity or concomitant pathology of other neurodegenerative disorders.

Methods: We screened 488 autopsy-confirmed PD cases for expansion haplotype tag rs3849942T. In 196 identified haplotype carriers, the C9ORF72 repeat was genotyped using the repeat-primed polymerase chain reaction assay.

Results: No larger (intermediate or expanded) repeats were found in these autopsy-confirmed PD samples. This absence of larger repeats is significantly different from the frequency in clinically diagnosed datasets (P = 0.002).

Conclusions: Our results suggest that expanded or intermediate C9ORF72 repeats in clinically diagnosed PD or parkinsonism might be an indication of heterogeneity in clinically diagnosed PD cases. Further studies are needed to elucidate the potential contribution of the C9ORF72 repeat to autopsy-confirmed PD.

Keywords: C9ORF72 repeat; Parkinson's disease; autopsy confirmed; parkinsonism.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Autopsy / methods*
  • C9orf72 Protein
  • Female
  • Genetic Predisposition to Disease / genetics*
  • Genotype
  • Humans
  • Male
  • Parkinson Disease / diagnosis*
  • Parkinson Disease / genetics*
  • Proteins / genetics*
  • Risk Factors
  • Trinucleotide Repeat Expansion / genetics*


  • C9orf72 Protein
  • C9orf72 protein, human
  • Proteins

Grant support