Mutation of the parkin gene (parkin) is the most common cause of early-onset Parkinson's disease and to date over 100 different mutations have been described. However, screening of parkin is complicated by its genomic architecture and context. Notably, dosage alterations in parkin account for greater than 50% of mutations detected in some cohort studies. To improve the accuracy and reproducibility of parkin genomic dosage assays we have identified and analysed cell lines with chromosomal abnormalities affecting 6q26. FISH and real-time PCR analysis identified cell lines with reduced or increased copy number spanning the entire parkin locus. These cell lines represent a valuable resource to facilitate accurate copy number determination of any parkin exon. The reagents are easily obtainable and are compatible with current quantitative technologies and platforms.