Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Epilepsy has many possible causes, including illness, brain injury, and abnormal brain development. In many cases, the cause is unknown.

Doctors use brain scans and other tests to diagnose epilepsy. It is important to start treatment right away. There is no cure for epilepsy, but medicines can control seizures for most people. When medicines are not working well, surgery or implanted devices such as vagus nerve stimulators may help. Special diets can help some children with epilepsy.

NIH: National Institute of Neurological Disorders and Stroke

Friedreich ataxia is an inherited disease that damages your nervous system. The damage affects your spinal cord and the nerves that control muscle movement in your arms and legs. Symptoms usually begin between the ages of 5 and 15. The main symptom is ataxia, which means trouble coordinating movements. Specific symptoms include:

• Difficulty walking
• Muscle weakness
• Speech problems
• Involuntary eye movements
• Scoliosis (curving of the spine to one side)
• Heart palpitations, from the heart disease which can happen along with Friedreich ataxia

People with Friedreich ataxia usually need a wheelchair 15 to 20 years after symptoms first appear. In severe cases, people become incapacitated. There is no cure. You can treat symptoms with medicines, braces, surgery, and physical therapy.

NIH: National Institute of Neurological Disorders and Stroke

A genetic brain disorder is caused by a variation or a mutation in a gene. A variation is a different form of a gene. A mutation is a change in a gene. Genetic brain disorders 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. They can also be due to a combination of both 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 have treatments to control symptoms. Some are life-threatening.

Guillain-Barre syndrome is a rare disorder that causes your immune system to attack your peripheral nervous system (PNS). The PNS nerves connect your brain and spinal cord with the rest of your body. Damage to these nerves makes it hard for them to transmit signals. As a result, your muscles have trouble responding to your brain. No one knows what causes the syndrome. Sometimes it is triggered by an infection, surgery, or a vaccination.

The first symptom is usually weakness or a tingling feeling in your legs. The feeling can spread to your upper body. In severe cases, you become almost paralyzed. This is life-threatening. You might need a respirator to breathe. Symptoms usually worsen over a period of weeks and then stabilize.

Guillain-Barre can be hard to diagnose. Possible tests include nerve tests and a spinal tap. Most people recover. Recovery can take a few weeks to a few years. Treatment can help symptoms, and may include medicines or a procedure called plasma exchange.

NIH: National Institute of Neurological Disorders and Stroke

Cholesterol is a waxy, fat-like substance that's found in all the cells in your body. Your liver makes cholesterol, and it is also in some foods, such as meat and dairy products. Your body needs some cholesterol to work properly. But having too much cholesterol in your blood raises your risk of coronary artery disease.

HDL and LDL are two types of lipoproteins.They are a combination of fat (lipid) and protein. The lipids need to be attached to the proteins so they can move through the blood. HDL and LDL have different purposes:

• HDL stands for high-density lipoproteins. It is sometimes called the "good" cholesterol because it carries cholesterol from other parts of your body back to your liver. Your liver then removes the cholesterol from your body.
• LDL stands for low-density lipoproteins. It is sometimes called the "bad" cholesterol because a high LDL level leads to a buildup of cholesterol in your arteries.

A blood test can measure your cholesterol levels, including HDL. When and how often you should get this test depends on your age, risk factors, and family history. The general recommendations are:

For people who are age 19 or younger::

• The first test should be between ages 9 to 11
• Children should have the test again every 5 years
• Some children may have this test starting at age 2 if there is a family history of high blood cholesterol, heart attack, or stroke

For people who are age 20 or older::

• Younger adults should have the test every 5 years
• Men ages 45 to 65 and women ages 55 to 65 should have it every 1 to 2 years

With HDL cholesterol, higher numbers are better, because a high HDL level can lower your risk for coronary artery disease and stroke. How high your HDL should be depends on your age and sex:

If your HDL level is too low, lifestyle changes may help. These changes may also help prevent other diseases, and make you feel better overall:

• Eat a healthy diet. To raise your HDL level, you need to eat good fats instead of bad fats. This means limiting saturated fats, which include full-fat milk and cheese, high-fat meats like sausage and bacon, and foods made with butter, lard, and shortening. You should also avoid trans fats, which may be in some margarines, fried foods, and processed foods like baked goods. Instead, eat unsaturated fats, which are found in avocado, vegetable oils like olive oil, and nuts. Limit carbohydrates, especially sugar. Also try to eat more foods naturally high in fiber, such as oatmeal and beans.
• Stay at a healthy weight. You can boost your HDL level by losing weight, especially if you have lots of fat around your waist.
• Exercise. Getting regular exercise can raise your HDL level, as well as lower your LDL. You should try to do 30 minutes of moderate to vigorous aerobic exercise on most, if not all, days.
• Avoid cigarettes.Smoking and exposure to secondhand smoke can lower your HDL level. If you are a smoker, ask your health care provider for help in finding the best way for you to quit. You should also try to avoid secondhand smoke.
• Limit alcohol. Moderate alcohol may lower your HDL level, although more studies are needed to confirm that. What we do know is that too much alcohol can make you gain weight, and that lowers your HDL level.

Some cholesterol medicines, including certain statins, can raise your HDL level, in addition to lowering your LDL level. Health care providers don't usually prescribe medicines only to raise HDL. But if you have a low HDL and high LDL level, you might need medicine.

Taking certain medicines can lower HDL levels in some people. They include:

• Beta blockers, a type of blood pressure medicine
• Anabolic steroids, including testosterone, a male hormone
• Progestins, which are female hormones that are in some birth control pills and hormone replacement therapy
• Benzodiazepines, sedatives that are often used for anxiety and insomnia

If you are taking one of these and you have a very low HDL level, ask your provider if you should continue to take them.

Diabetes can also lower your HDL level, so that gives you another reason to manage your diabetes.