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Classic (or neutral) pathways of bile acid biosynthesis

Selected enzymes are shown in red boxes. The red arrows show the abnormal synthetic step in cerebrotendinous xanthomatosis, which is due to deficiency or dysfunction of the enzyme cytochrome P450 27A1 (CYP27A1). The rate-limiting enzyme that initiates the classic pathways is cytochrome P450 7A1 (CYP7A1, or cholesterol 7 alpha-hydroxylase). (Illustration by Dr. Douglas J Lanska.)

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Associated Disorders

  • Ataxia
  • Behavioral problems
  • Bone fractures
  • Bulbar palsy
  • Cerebellar syndrome
  • Chronic diarrhea in children
  • Degenerative CNS disease
  • Dementia
  • Epileptic seizures
  • Gallstones
  • Ischemic heart disease
  • Juvenile cataracts
  • Kidney stones
  • Leukoencephalopathy
  • Marinesco-Sjogren syndrome
  • Mental retardation
  • Mitochondrial myopathy
  • Myelopathy
  • Myopathic-like faces
  • Nephrocalcinosis
  • Nephrolithiasis
  • Neurometabolic disease
  • Osteoporosis
  • Paraparesis
  • Paraplegia
  • Parkinsonism
  • Peripheral polyneuropathy
  • Pes cavus
  • Pontocerebellar degeneration
  • Psychiatric disorders
  • Xanthomata