FDX1 and congenital adrenal hyperplasia: As discussed in the ‘Lipoid CAH’ section above, lipoid CAH was initially thought to be a defect in P450scc, but no defects were found in P450scc, ferredoxin (FDX), ferredoxin reductase (FDXR) or in some factors thought to facilitate cholesterol’s entry into the mitochondria.