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What is CTX?

Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder affecting the proper breakdown of cholesterol.

CTX is caused by defects in the CYP27A1 gene leading to a deficiency of a crucial enzyme thus interrupting cholesterol breakdown into primary bile acids, chenodeoxycholic acid (CDCA) and cholic acid (CA). This results in a deficiency of these primary bile acids, especially of CDCA as CA is also produced through an alternate mechanism not requiring the enzyme that is affected. The deficiency of primary bile acids disrupts how cholesterol is normally removed and leads to an increase in abnormal toxic compounds and an abnormal accumulation of lipids in the body.

The disease is characterized by the abnormal storage of these lipids in various areas of the body, causing potentially devastating, progressive symptoms in the eyes, tendons, and central nervous system. CTX affects patients’ long-term health and quality of life.1,2

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CTX is one of a group of inherited neurologic disorders known as leukodystrophies. Leukodystrophies affect the cerebral white matter — the part of the brain that carries nerve impulses, electrical signals that stimulate or inhibit the action of a muscle, gland, or other nerve cell. Leukodystrophies are characterized by progressive deterioration of the myelin sheath, the covering that protects nerve fibers and speeds up the transmission of nerve impulses.3

The name cerebrotendinous xanthomatosis is derived from the accumulation of lipids in the brain and tendons – “cerebro-” meaning brain and “-tendinous” referring to tendons. Researchers now know that CTX involves additional vital organs and body systems.

A Progressive Disease

Hear more from CTX experts.

Concerns About CTX?

If you are suspicious of or diagnosed with CTX, please seek your local healthcare practitioners for professional consultation, as practice and referral systems vary from country to country.


  1. Federico A, Dotti MT, Gallus GN. Cerebrotendinous xanthomatosis. In: Adam MP, Ardinger HH, Pagon RA et al, editors. Gene Reviews [Internet]. Seattle: University of Washington; 2013; updated 2016. Accessed 25 January 2018.
  2. Steiner RD. Cerebrotendinous xanthomatosis. Medscape; 2015; updated 2017. Accessed 29 January 2018.
  3. Köhler W, Curiel J, Vanderver A. Adulthood leukodystrophies. Nature Reviews Neurology. 2018. Feb;14(2):94-105.
CTX Awareness