Our results indicate that to analyze the relationship between dopa-responsive dystonia-related genes and PD, it is important to screen GCH1 and test rs6356 of TH in a larger sample.
PD subjects homozygous for the common V81M polymorphism, have higher overall freezing of gait scores after controlling for disease duration, although this polymorphism does not associate with the occurrence of PD or FOG.
A common amino-acid polymorphism in COMT, valine-108-methionine, results in a low activity form of the enzyme which we hypothesised may influence susceptibility to IPD.