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MIM.603711 8q21.3

Monday 25 February 2008

The synthesis of primary bile acids from cholesterol occurs via 2 pathways: the classic neutral pathway involving cholesterol 7-alpha-hydroxylase (CYP7A1) (MIM.118455), and the acidic pathway involving a distinct microsomal oxysterol 7-alpha-hydroxylase (CYP7B1).

In the liver, CYP7B1 offers an alternative pathway for cholesterol degradation and also provides the primary metabolic route for the modification of dehydroepiandrosterone neurosteroids in the brain.


- germline mutations of CYP7A1 in congenital bile acid synthesis defect type 3(MIM.603711)

- sequence alterations of CYP7A1 in this pure form of hereditary spastic paraplegias (HSPs) with motor-neuron degeneration (18252231)

  • The hereditary spastic paraplegias (HSPs) are a genetically and clinically heterogeneous group of upper-motor-neuron degenerative diseases characterized by selective axonal loss in the corticospinal tracts and dorsal columns.
  • Although numerous mechanisms involving defective subcellular transportation, mitochondrial malfunction, and increased oxidative stress have been proposed, the pathogenic basis underlying the neuronal loss is unknown.

See also

- cholesterol metabolism
- bile acids metabolism


- Tsaousidou MK, Ouahchi K, Warner TT, Yang Y, Simpson MA, Laing NG, Wilkinson PA, Madrid RE, Patel H, Hentati F, Patton MA, Hentati A, Lamont PJ, Siddique T, Crosby AH. Sequence alterations within CYP7B1 implicate defective cholesterol homeostasis in motor-neuron degeneration. Am J Hum Genet. 2008 Feb;82(2):510-5. PMID: 18252231