What is Cerebrotendinous Xanthomatosis?
Cerebrotendinous xanthomatosis (CTX) is a disease that leads to increased storage in the body of fats such as cholesterol. CTX is caused by harmful genetic changes (mutations) in the CYP27A1 gene. CYP27A1 deficiency leads to an inability to breakdown cholesterol and a toxic buildup of fats in the body.
Common features of this disorder include diarrhea that starts in infancy; clouding of the lens of the eye (cataracts); deposits of fat under the skin (xanthomas); and neurologic problems that get worse over time. For many affected individuals, chronic diarrhea beginning in infancy is the earliest symptom. Typically, sufferers develop cataracts during early childhood. Xanthomas most commonly begin appearing in adolescence and early adulthood, often on the Achilles tendon (on the back of the heel) and other tendons, though they can occur throughout the body. Most individuals with CTX have no or only mild neurologic problems before puberty. Beginning in their twenties, patients can develop neurologic symptoms such as seizures and an inability to control movements (ataxia). These symptoms will often worsen over time. Additional neurological features may include intellectual disability, dementia, and mental health problems such as depression or hallucinations. Some other reported features of CTX include weak and brittle bones (osteoporosis) and heart problems.
How common is Cerebrotendinous Xanthomatosis?
Currently, there is no consensus on the global incidence of this disorder. The condition is more common in the Druze population in Israel and in Sephardic Jews of Moroccan descent. The incidence in individuals of European descent is at least 1 in 50,000.
How is Cerebrotendinous Xanthomatosis treated?
There is no cure for CTX, but early diagnosis and treatment with chenodeoxycholic acid (CDCA) can prevent or reduce the symptoms. Other treatments are based on the presentation of the disease; for instance, medication is used for seizures and trouble controlling movements, and calcium and vitamin D are used for weak and brittle bones. Eye surgery to remove cataracts is often required in adulthood.
What is the prognosis for an individual with Cerebrotendinous Xanthomatosis?
The prognosis for CTX is greatly improved if the disease is identified and treated early. Treatment may prevent the development of some symptoms, although it may not be able to reverse all features once the disease has progressed. In addition, patients' lifespans may be normal if treatment begins early. Without treatment, the average lifespan is 50-60 years, due to progressive deterioration.