G/A polymorphism in intronic sequence affects the processing of MAO-B gene in patients with Parkinson disease

► Elevated levels of MAO B protein expression detected in PD patient blood fraction.. ► Intron 13 containing “A” allele is removed from pre-mRNA more efficiently. ► SR proteins interact more efficiently with pre-mRNA sequence containing A allele. ► Stronger SR protein interacion influences intron removal from MAO-B pre-mRNA. Monoamine oxidase B (MAO-B) plays an important role in the metabolism of neuroactive and vasoactive amines in the central nervous system and peripheral tissues. Increased levels of MAO-B mRNA and enzymatic activity have been reported in platelets from patients with Parkinson’s and Alzheimer’s diseases, however the triggers of enhanced mRNA levels are unknown. Our results demonstrate for the first time that G/A dimorphism in intron 13 sequence creates splicing enhancer thus stimulating intron 13 removal efficiency. The increased MAO-B protein levels might serve as a surrogate marker for – Parkinson disease.