About Amyotrophic Lateral Sclerosis
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
Amyotrophic lateral sclerosis (ALS), also referred to as “Lou Gehrig’s disease,” is a motor neuron disease which leads to problems with muscle control and movement. There are various types of ALS that are distinguished by symptoms and, in some cases, genetic cause. Early symptoms may include muscle twitching, cramping, stiffness, or weakness, slurred speech, and/or difficulty chewing or swallowing. As the disease progresses, people may become weaker and are eventually wheelchair-dependent. Most people with ALS have a sporadic (not inherited) form of ALS. It is believed that these cases are caused by an interaction between genetic and environmental factors. This means that a person may have inherited genetic changes (pathogenic variants) that increase their risk to develop ALS, but the person will only develop ALS if exposed to certain environmental triggers. About 10% of the people with ALS have at least one relative with the disease and are said to have have a familial (inherited) form of the disease (FALS). Familial ALS may be caused by genetic changes (pathogenic variants) in any one of several genes and the pattern of inheritance varies depending on the gene involved. The distinction between sporadic and familial cases is not always clear. Diagnosis of ALS is based on symptoms and a variety of tests to rule out other possible medical diseases that can cause similar symptoms.
Causes
Can This Disease Be Passed Down From Parent to Child?
Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.
There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):
Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.
People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.
Autosomal Recessive: Autosomal means the gene involved is located on one of the numbered chromosomes. Recessive means that a child must inherit two copies of the mutated gene, one from each biological parent, to be affected by the disease. A carrier is a person who only has one copy of the genetic mutation. A carrier usually doesn’t show any symptoms of the disease.
If both biological parents are carriers, there is a 25% chance their child inherits both copies of the mutated gene and is affected by the disease. Additionally, there is a 50% chance their child inherits only one copy of the mutated gene and is a carrier.