Lack of association between G-protein coupled receptor kinase 5 gene and Parkinson's disease

The major component of Lewy Bodies (LB), the pathological hallmark of Parkinson’s disease (PD) is a-synuclein, most prominently phosphorylated at serine 129. G-protein coupled receptor kinase 5 (GRK5) has been reported to phosphorylate a-synuclein in vitro, enhancing the a-synuclein toxicity to dopaminergic neurons in Drosophila model. Moreover, GRK5 was found in LBs from brain of PD patients. A genetic association study performed in the Japanese population revealed haplotypic association of the GRK5 gene with susceptibility to sporadic PD. We aimed at investigating whether four polymorphisms within the GRK5 gene (rs871196, rs2420616, rs7069375, rs4752293) could represent a risk factor for sporadic PD in Southern Italy. We genotyped 446 patients with PD and 450 controls for these markers and did not find any significant association with the disease at allelic, genotypic and haplotypic level. Our results indicate that the GRK5 gene does not confer risk to sporadic PD in our sample from Southern Italy.