["To ascertain whether a coding mutation (Ile93Met) in ubiquitin carboxy-terminal hydrolase (UCH-L1) gene plays a role in idiopathic Parkinson's disease (IPD).", 'Polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP) was used to distinguish the wild-type (two DNA fragments of 34 and 126 bp) from the variant allele (three fragments of 34, 60 and 66 bp) because the mutation created a new site for restriction endonuclease BsmF1. DNA was isolated from various blood samples using a phenolchloroform extraction.', 'Ile93Met substitution was found neither in PD patients nor in controls.'] Is an Ile93Met substitution in the UCH-L1 gene a disease-causing mutation for idiopathic Parkinson 's disease?