What is (are) cerebrotendinous xanthomatosis ?
Cerebrotendinous xanthomatosis is a fat (lipid) storage disorder that affects many areas of the body. People with this disorder cannot break down certain lipids effectively, specifically different forms of cholesterol, so these fats accumulate in various areas of the body. Xanthomatosis refers to the formation of fatty yellow nodules (xanthomas). Cerebrotendinous refers to the typical locations of the xanthomas (cerebro- meaning the brain and -tendinous meaning connective tissue called tendons that attach muscle to bone).  Other features of cerebrotendinous xanthomatosis include chronic diarrhea during infancy, clouding of the lens of the eye (cataracts) developing in late childhood, progressively brittle bones that are prone to fracture, and neurological problems in adulthood, such as dementia, seizures, hallucinations, depression, and difficulty with coordinating movements (ataxia) and speech (dysarthria). The neurological symptoms are thought to be caused by an accumulation of fats and an increasing number of xanthomas in the brain. Xanthomas can also accumulate in the fatty substance that insulates and protects nerves (myelin), disrupting nerve signaling in the brain. Disorders that involve the destruction of myelin are known as leukodystrophies. Degeneration (atrophy) of brain tissue caused by excess lipid deposits also contributes to the neurological problems.  Xanthomas in the tendons (most commonly in the Achilles tendon, which connects the heel of the foot to the calf muscles) begin to form in early adulthood. Tendon xanthomas may cause discomfort and interfere with tendon flexibility. People with cerebrotendinous xanthomatosis are also at an increased risk of developing cardiovascular disease. If untreated, the signs and symptoms related to the accumulation of lipids throughout the body worsen over time; however, the course of this condition varies greatly among those who are affected.