Fig. 1.

Bile acid biosynthesis starting with 7-DHC and ending with GlcNAc conjugates of 3β,7β-diH-Δ⁵-BA. The metabolites of elevated abundance found in plasma from SLOS patients are indicated by an upward pointing blue arrow and those elevated in amniotic fluid from SLOS affected pregnancies by an upward pointing red arrow. Metabolites of elevated abundance found in SLOS urine are indicated by a green upwards pointing arrow. Oxysterols, including C₂₄ and C₂₇ acids, found in plasma are shown in blue, bile acid conjugates found in urine are in green. The enzyme(s) for each step is in black. There is also minor non-enzymatic formation of 7−OC which may be more important in some lysosomal storage disorders [30]. Systematic and common names of molecular structures can be found in Supplemental Tables 1 & 2. For simplicity 3β,7β,24-triHCA is shown as the carboxylic acid rather than the CoA thioester. The 7-oxocholesterol 25-hydroxylase is not known, many CYP enzymes, and also CH25H, have sterol 25-hydroxylase activity.