Interestingly, Björkhem and coworkers found that the level of oxysterols in the cerebrospinal fluid may reflect neurodegenerative changes occurring in PD patients (Björkhem et al., 2013), which is in line with the association between SNPs in CYP39A1 and CYP7B1 and the manifestation of PD symptoms found in our study. The gene discussed is CYP39A1; the disease is Parkinson disease.