NMNAT2 and Parkinson disease: The microarray dataset GSE7621 was used for the analysis of mRNA levels of NADSYN1 and NMNAT in the SN of PD patients, which showed decreased NMNAT2 mRNA level in the SN of PD patients, while the mRNA levels of NADSYN1, NMNAT1, and NMNAT3 were not significantly different (Fig. 4B, C).