Intriguingly, concentrations of 7α-HC, 7α-HCO, 7β-HC, and 7O-C, which originate from the CYP7A1-initiated arm of the bile acid biosynthesis pathway and enter the CSF from the circulation, did not differ between ALS patients and controls (Fig. 5). The gene discussed is CYP7A1; the disease is amyotrophic lateral sclerosis.