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Research paper
A study of up to 12 years of follow-up of Friedreich ataxia utilising four measurement tools
  1. Geneieve Tai1,
  2. Louise A Corben1,2,
  3. Lyle Gurrin3,
  4. Eppie M Yiu1,4,5,
  5. Andrew Churchyard2,
  6. Michael Fahey6,
  7. Brian Hoare2,
  8. Sharon Downie2,
  9. Martin B Delatycki1,2,4,6,7
  1. 1Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
  2. 2Monash Health, Clayton, Victoria, Australia
  3. 3Department of Molecular, Environmental, Genetic and Analytic Epidemiology, University of Melbourne, Parkville, Victoria, Australia
  4. 4Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
  5. 5Children's Neuroscience Centre, Royal Children's Hospital, Parkville, Victoria, Australia
  6. 6Department of Paediatrics, Monash University, Clayton, Victoria, Australia
  7. 7Department of Clinical Genetics, Austin Health, Heidelberg, Victoria, Australia
  1. Correspondence to Professor Martin B Delatycki, Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Flemington Rd, Parkville, VIC 3052, Australia; martin.delatycki{at}


Objective To explore the progression of Friedreich ataxia by analysing the change in scores of four clinical measures (the Friedreich Ataxia Rating Scale (FARS), the International Cooperative Ataxia Rating Scale (ICARS), the Functional Independence Measure (FIM) and the Modified Barthel Index (MBI)) over a period of up to 12 years, to ascertain the effects of clinical variables on performance of these measures, and to determine the most sensitive rating scale for measuring disease progression.

Methods We measured the disease progression of up to 147 individuals against disease duration grouped into 5-year intervals. Additional subgroups were created to study the effects of the size of the smaller FXN intron 1 GAA repeat size (GAA1) and onset age on rating scale performance.

Results Both the FARS and ICARS demonstrated greater change in the first 20 years post disease onset than in the subsequent 20 years during which there was little change in the mean score. While the FIM and MBI continued to deteriorate beyond 20 years post disease onset, floor effects were noted. As measured by the FARS, individuals with a larger GAA1 repeat were found to progress more quickly in the first 20 years of disease.

Conclusions Individuals with larger GAA1 repeat sizes and earlier ages of disease onset were shown to deteriorate at a faster rate and were associated with greater FARS and ICARS scores and lower FIM and MBI scores, which are indicative of greater disease severity.


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