FALS PROGRESSION

If diagnosed with FALS, is it likely that the progression of the disease will be similar to the earlier family member that had it?

[Lisa Kessler, MS, CGC]

As you may know, approximately 10% of amyotrophic lateral sclerosis (ALS) cases are familial (FALS).  As you know, ALS is a neurodegenerative disorder in which motor neurons (nerve cells that communicate to muscle cells) in the brain, brainstem, and spinal cord die.  This causes paralysis and death.  ALS usually begins in middle adult life, and the lifetime risk of developing ALS is 1 in 800.  

One gene, called SOD1, causes 20% of familial ALS, and molecular testing for this gene is available on a clinical basis.  ALS associated with the SOD1 gene is inherited in an autosomal dominant way, which means that someone with the condition has a 50% chance of passing it on.  However, not everyone with the gene mutation develops the condition.   ALS can also be inherited in autosomal recessive or an X-linked dominant way and can be due to other factors.  

In addition to some family members carrying the gene mutation and never having symptoms of FALS, one review describes variability in disease progression and age of onset in family members.  One example is age of onset varying over 30 years.  So it is not always possible to predict the progression of the disease based on family member's experiences.  

Someone with FALS or a family history of FALS may benefit from meeting with a genetic counselor to learn more about FALS and if genetic testing is appropriate.  You can find a genetic counselor through the NSGC’s website.