NOS2 and Parkinson disease: The analysis results showed that the A allele of rs2072324, A allele of rs3794764, G allele of rs12944039 (p < 0.0001), A allele of rs2297516 (p < 0.0001), and T allele of rs2255929 (p < 0.0001) of the NOS2 gene were associated with a risk for PD in 337 families with sporadic PD at ages between 40 and 80.