Main Types of ASL

 
What Are the Main Types?

There are two types of ALS:

Sporadic ALS is the most common form. It affects up to 95% of people with the disease. Sporadic means it happens sometimes without a clear cause.

    Familial ALS (FALS) runs in families. About 5% to 10% of people with ALS have this type. FALS is caused by changes to a gene. Parents pass the faulty gene to their children. If one parent has the gene for ALS, each of their children will have a 50% chance of getting the gene and having the disease.

What Causes ALS?

Researchers still don't know exactly what causes motor neurons to die with ALS. Gene changes, or mutations, are behind 5% to 10% of ALS cases. More than 12 different gene changes have been linked to ALS.

One change is to a gene that makes a protein called SOD1. This protein may be toxic to motor neurons. Other gene changes in ALS might also damage motor neurons.

Environment could also play a role in ALS. Scientists are studying whether people who come into contact with certain chemicals or germs are more likely to get the disease. For example, people who served in the military during the 1991 Gulf War have gotten ALS at higher rates than usual.