Association of IGF1 gene polymorphism with Parkinson's disease in a Han Chinese population

Background Accumulating evidence suggests that insulin-like growth factor 1 (IGF1) plays an important role in Parkinson's disease (PD) pathogenesis. However, it is not clear if IGF1 polymorphism contributes to PD risk. Methods We performed a case-control study in a Han Chinese population that included 512 sporadic PD cases and 535 matched controls. All participants were genotyped for rs972936 using the Sequenom MassARRAY iPLEX platform. Serum IGF1 levels of 61 de novo, drug-naive PD patients, and 55 age- and sex-matched controls were also measured by enzyme-linked immunosorbent assay (ELISA). Results Genotype frequency of rs972936-CC was significantly associated with increased PD risk (P = 0.009), especially in males (P = 0.024) and late-onset patients (P = 0.013). Serum IGF1 levels were significantly increased in de novo, drug-naive PD patients compared with controls (P = 0.036), but were not correlated with motor dysfunction in PD patients (P = 0.220). Conclusions Our study shows that rs972936 polymorphism may increase susceptibility to PD, especially in males and late-onset patients. Further, high serum IGF1 levels may be a potential diagnostic biomarker for PD in the Han Chinese population, but does not correlate with more severe motor dysfunction.