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Genetic Brain Disorder
A genetic disorder is a disease caused by a different form of a gene, called a variation, or a change in a gene, called a mutation. Genetic brain disorders specifically affect the development and function of the brain. Some genetic brain disorders are due to random gene mutations or mutations caused by environmental exposure, such as cigarette smoke. Other disorders are inherited, which means that a mutated gene or group of genes is passed down through a family. Still other disorders are due to a combination of genetic changes and other outside factors. Some examples of genetic brain disorders include
- leukodystrophies
- phenylketonuria
- Tay-Sachs disease
- Wilson disease
Many people with genetic brain disorders fail to produce enough of certain proteins that influence brain development and function. These brain disorders can cause serious problems that affect the nervous system. Some are life-threatening.
Leukodystrophies:
The leukodystrophies are rare diseases that affect the cells of the brain. Specifically, the diseases affect the myelin sheath, the material that surrounds and protects nerve cells. Damage to this sheath slows down or blocks messages between the brain and the rest of the body. This leads to problems with
- Movement
- Speaking
- Vision
- Hearing
- Mental and physical development
Most of the leukodystrophies are genetic. They usually appear during infancy or childhood. They can be hard to detect early because children seem healthy at first. However, symptoms gradually get worse over time.
There are no cures for any of the leukodystrophies. Medicines, speech therapy and physical therapy might help with symptoms. Researchers are testing bone marrow transplantation as a treatment for some of the leukodystrophies.
Phenylketonuria:
Also called: PKU
Phenylketonuria (PKU) is a genetic disorder in which the body can't process part of a protein called phenylalanine (Phe). Phe is in almost all foods. If the Phe level gets too high, it can damage the brain and cause severe mental retardation. All babies born in U.S. hospitals must now have a screening test for PKU. This makes it easier to diagnose and treat the problem early.
The best treatment for PKU is a diet of low-protein foods. There are special formulas for newborns. For older children and adults, the diet includes many fruits and vegetables. It also includes some low-protein breads, pastas and cereals. Nutritional formulas provide the vitamins and minerals they can't get from their food.
Babies who get on this special diet soon after they are born develop normally. Many have no symptoms of PKU. It is important that they stay on the diet for the rest of their lives.
Tay-Sachs disease:
Tay-Sachs disease is a rare, inherited disorder. It causes too much of a fatty substance to build up in tissues and nerve cells of the brain. This buildup destroys the nerve cells, causing mental and physical problems.
Infants with Tay-Sachs disease appear to develop normally for the first few months of life. Then, as nerve cells become distended with fatty material, mental and physical abilities deteriorate. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy and paralysis sets in. Even with the best of care, children with Tay-Sachs disease usually die by age 4.
Tay-Sachs is most common in Eastern European Ashkenazi Jews. A blood test can determine if you carry or have the disease. There is no cure. Medicines and good nutrition can help some symptoms. Some children need feeding tubes.
Wilson disease:
Also called: Hepatolenticular degeneration
Wilson disease is a rare inherited disorder that causes your body to retain copper. Normally, your liver releases copper it doesn't need into bile, a digestive fluid. With Wilson disease, this does not happen. Copper builds up in your liver and injures liver tissue. Over time, the damage causes your liver to release the copper directly into your bloodstream. The blood carries copper all over your body. Too much copper can damage your kidneys, liver, brain and eyes.
Usually the build-up of copper starts after birth. Symptoms usually start between ages 6 and 20, but can begin as late as age 40. The most characteristic sign is a rusty brown ring around the cornea of the eye.
If you have Wilson disease, you will have to take medicine and follow a low-copper diet for the rest of your life. With early detection and proper treatment, a person with Wilson disease can enjoy normal health.