What is Cerebrotendinous Xanthomatosis?

Often referred to as “CTX”, cerebrotendinous xanthomatosis is a rare inherited condition present from birth. Those with this condition develop an excessive amount of fat in multiple organs throughout the body, interfering with proper functioning and resulting in a variety of health problems. This abnormal collection of fat is particularly prominent in tendons, which attach muscle to bone, and in the brain.

What are the effects of CTX?

Symptoms related to this condition are variable. In general, most individuals with CTX experience:

  • Diarrhea
  • Cataracts which cause vision problems
  • Thickening of tendons, resulting in pain and swelling

The abnormal accumulation of fat in the brain leads to progressive problems with the nervous system, resulting in seizures, abnormal muscle movements, trouble maintain balance, difficulty speaking clearly, loss of feeling in the arms and legs, dementia, hallucinations, and depression. Other symptoms include an increased risk of bone fractures, due to loss of calcium, and an increased risk of developing heart or lung failure at an early age.

What causes CTX?

Individuals with CTX are unable to make bile acids correctly. Bile acids are produced in the body to help break down fats, allowing for normal daily activities and good health. Because the body lacks proper amounts of bile acid in those with CTX, there is a buildup of fat in many organs, including the brain, which causes problems with normal function and may lead to organ failure. In addition, there is often a built up of other chemicals that can damage the body’s organs.

CTX is an inherited condition. Although neither the child’s mother nor father is affected, the condition is passed down when the child receives one affected copy of the gene causing CTX from each parent. Genes help determine everything from the color of our eyes to how our body’s work. The presence of 2 affected copies of the CTX gene (one from the mother and the other from the father) causes the child to have the condition. When both parents are carriers of the CTX gene the risk of having an affected child is 25%, each time these parents decide to have a child.

How can you tell if someone has CTX?

CTX is often suspected in individuals when typical signs and symptoms are present. Symptoms, which are often present in infants, generally develop during the first and second decades of life. A blood test can detect the presence of abnormal bile acids and fats. Imaging, such as with an MRI scan, may show typical changes of CTX in the brain. Genetic tests can be performed to confirm that a person is affected by CTX, as well as identify carriers of the CTX gene. Although not affected by the condition themselves, identifying carriers of the CTX gene can help parents make decisions about future pregnancies.

Is CTX curable?

There is no known cure for CTX. However, replacing the missing bile acid with a daily oral supplement has helped those with CTX improve their health. Medications to lower levels of “bad” cholesterol, which can damage blood vessels and lead to heart disease at an early age, as well as some dietary supplements are also helpful. Surgery, to remove cataracts, can improve vision.