Cholestane-3β,5α,6β-triol is a marker of presentation and the worsening of Wolman's disease (90); it is likely to be formed by cholesterol epoxide hydrolase (a dimer of 7-DHC reductase [DHCR7] and Δ8-Δ7 isomerase and emopamil binding protein sterol isomerase [EBP]), two enzymes of the cholesterol biosynthesis pathway, catalyzed hydration of 3β-hydroxycholestane-5,6-epoxide (5,6-epoxycholesterol) (91), a nonenzymatic product of cholesterol (92, 93), potentially formed in mitochondria under oxidative stress in Wolman's disease. The gene discussed is DHCR7; the disease is Wolman disease.