1. Most Cases of ALS Are Not Hereditary
Only five to 10 percent of ALS cases are hereditary and are known as familial ALS. Familial ALS can be linked to mutations in specific chromosomes in our DNA, or our "blueprints." The vast majority of ALS cases are not hereditary and are believed to be caused by factors in our environment, or some other as yet unknown causes. If you are concerned about a history of ALS in your family, talk to your doctor about your risks.
2. How Do You Get Tested for ALS?
Some forms of familial ALS have been identified through genetic markers. A simple blood test can check for these markers. Genetic testing is very expensive, however, and can take several weeks or months to obtain test results. If you are concerned about your risk for ALS, speak with your doctor or a genetic counselor to see if genetic testing is appropriate for you.
3. Should You Be Tested for Familial ALS?
There are genetic markers for ALS that have not been identified, so a negative genetic test may not mean you are not at risk. Also, many people who do have the genetic markers for ALS have never shown symptoms. A positive genetic test result can cause a significant amount of mental and emotional stress from worrying that you will develop the disease when in reality, you may never develop symptoms. This stress can damage your health in other ways. Discuss the benefits and pitfalls of genetic testing for ALS with your doctor before you are tested.
4. What If You Test Positive for Familial ALS?
Even if you test positive for one of the genetic markers associated with a familial form of ALS, this is not the same as being diagnosed with ALS. It does not mean that you have ALS. Many people who carry the genetic marker will not ever show symptoms of ALS, and no one understands what actually triggers the development of symptoms. If you do have the genetic basis for ALS, you can take extra steps to live a healthier life, which may assist in preventing development of ALS symptoms.
5. Will You Pass the Risk of ALS to Your Children?
It is possible to have prenatal testing or genetic counseling done if you are concerned about passing the risk of ALS along to your children. Remember that a family history of ALS does not mean that you or your children will develop the disease. The majority of ALS cases are not genetically based, not everyone who has the genetic marker will develop symptoms of the disease, and not every child born in a family with a history of ALS will even have the genetic marker. Speak with your doctor or a genetic counselor who can review your family health history and help you understand the true chances of your child being affected with ALS.
