Cerebrotendinous Xanthomatosis (CTX)
Description
Cerebrotendinous Xanthomatosis (CTX) is a rare, inherited disorder that affects cholesterol metabolism. This condition leads to the buildup of cholesterol in various tissues throughout the body, causing a range of health problems. While CTX is relatively uncommon, understanding its characteristics, causes, and treatment options is crucial for individuals and families affected by it.
Genes Involved
CTX is caused by mutations in the CYP27A1 gene. This gene provides instructions for making an enzyme called sterol 27-hydroxylase. This enzyme plays a critical role in the breakdown of cholesterol in the body. When the CYP27A1 gene is mutated, this enzyme doesn‘t function properly, leading to the buildup of cholesterol.
Recognizing the Signs and Symptoms
Recognizing the Signs and Symptoms of CTX can be challenging as they often manifest differently in individuals. Some common signs include:
- Tendon xanthomas: Yellow, fatty deposits appearing near tendons, particularly around the Achilles tendon, elbows, and knees.
- Corneal arcus: A white or gray ring around the cornea of the eye, similar to a gray halo around the iris.
- Progressive neurological problems: CTX can affect the brain and spinal cord, leading to issues like ataxia (lack of coordination), dementia, and seizures.
- Liver disease: The buildup of cholesterol can cause liver damage and ultimately lead to cirrhosis.
- Gallstones: Increased cholesterol in the bile can lead to gallstones, causing pain and discomfort in the abdomen.
- Early onset atherosclerosis: CTX can increase the risk of heart disease and stroke due to cholesterol deposits in blood vessels.
Causes
CTX is caused by an inherited genetic mutation. Individuals with CTX inherit a defective CYP27A1 gene from one or both parents. If both parents carry the mutation, their child has a 50% chance of inheriting the condition. If only one parent carries the mutation, their child has a 25% chance of inheriting it.
Inheritance/recurrence risk
CTX follows an autosomal recessive inheritance pattern. This means that both parents must carry the defective gene for their child to inherit the condition. If one parent has CTX and the other parent is a carrier, there is a 50% chance their child will be a carrier and a 50% chance their child will inherit CTX. If both parents have CTX, their child will inherit the condition.
