The role of alpha-synuclein gene multiplications in early-onset Parkinson's disease and dementia with Lewy bodies.

BACKGROUND: A triplication of the alpha-synuclein gene was found to cause autosomal dominant Lewy body disease in two distinct families. METHOD: We searched for alterations of alpha-synuclein gene dosage and analysed the entire coding region for point mutations in 54 dementia with Lewy body disease (DLB) and in 103 young onset Parkinson's disease (PD) patients from Central Europe. RESULTS: We could not detect any quantitative alterations in the gene dosage of alpha-synuclein. Mutational screening of the entire coding region of alpha-synuclein revealed only one silent mutation V3V (adenine9guanine) in one case. CONCLUSIONS: Thus, this phenomenon appears not to be a major cause in the pathogenesis of sporadic DLB and young onset PD in this European population.