Researchers studied 650 patients between ages 63-91, including 200 healthy patients and 450 with Parkinson's disease. They analyzed DNA markers for three polymorphisms of nitric oxide (NO) synthase enzymes (eNOS, nNOS, iNOS) that some research linked to loss of dopaminergic neurons in the substantia nigra pars compacta. The researchers found no association between these NO polymorphisms and Parkinson's disease.

1. Huerta et al.2007.No association between Parkinson’s disease and three polymorphism in the eNOS,
nNOS, and iNOS genes. Biochemistry Journal 463.202-205
First of all the researchers establish that some research found a relation between the synthesis of three
polymorphism of NO and the los of dopaminergic neurons in the substancia nigra pars compacta. The
researchers use a population of 200 of healthy patients and 450 patients between 63 years to 91. They
dehydrate the DNA marks and they found that there was not a relation between NO polymorphism and
Parkinson Disease. This paper is important to my work because the NO is produce mainly in the
mitochondria of the cell.