Multiplex ligation-dependent probe amplification assay for simultaneous detection of Parkinson's disease gene rearrangements.

Parkinson's disease (PD) is a common disorder caused by degeneration of dopaminergic neurons in the substantia nigra and other brain areas. Mutations in several genes have been associated with both autosomal dominant PD and recessive early onset Parkinsonism (EOP). Genomic rearrangements such as deletions or multiplications of one or more exons represent a common mutational mechanism for most of these genes and are not detectable with routine mutation screening techniques. MLPA (Multiplex Ligation-dependent Probe Amplification), is a cheap, simple, rapid, and sensitive tool to detect exon dosage alterations and specific point mutations in selected genes. We tested the recently developed PD-MLPA assay by using 13 positive control samples carrying known mutations in SNCA, LRRK2, Parkin, PINK1, and DJ-1 genes. We then applied this technique to screen 16 EOP patients who were then cross-tested by quantitative PCR (qPCR). All the mutations present in the positive control samples were clearly detected by MLPA. Moreover, three novel Parkin rearrangements were identified among EOP patients and confirmed by qPCR. Only two samples generated false positive duplications of LRRK2 exon 1 and UCH-L1 exon 9, respectively. These results show that PD-MLPA assay can simultaneously and effectively detect rearrangements in most PD genes (SNCA, Parkin, PINK1, and DJ-1) as well as the LRRK2 G2019S common mutation. Thus, the use of this novel platform can improve the analysis of such mutations, facilitating comprehensive genetic testing in PD and EOP.