The first under-expressed segment, with the lowest expression value in PD patients, was located on chromosome 5 [coordinates 76,000,001–76,500,000] (Table 2), with two known genes that are characterized by a statistically significant under-expression in substantia nigra of PD patients: SV2C and IQGAP2, encoding respectively for synaptic vesicle glycoprotein 2C and a member of the IQGAP (IQ motif containing GTPase activating protein) family. This evidence concerns the gene IQGAP2 and Parkinson disease.