Amyotrophic Lateral Sclerosis

Hi Genetic Counselor,

I would like to seek your advice and expertice. In 1999 my grandma (on my dad's side) passed away with what was expected to be a slight case of amyotrophic lateral sclerosis. The symptoms that were present when she passed away is what lead to the suspected case of amyotrophic lateral sclerosis. In 2003, I had an aunt on my dad's side who passed away with a diagnosis of amyotrophic lateral sclerosis. I was wondering what risk I have for developing amyotrophic lateral sclerosis when I reach my 30's and 40's? Right now I'm 26 years old. There hasn't been anyone on my mom's side that has had amyotrophic lateral sclerosis besides cancer (which is not indicative of being genetically inherited due to age of onset).

Is there any genetic test currently that I can get done to test for mutations in the genes that can cause amyotrophic lateral sclerosis?

P.S. I'm a prospective genetic counseling student

[Lisa Kessler, MS, CGC]

Approximately 10% of amyotrophic lateral sclerosis (ALS) cases are familial.  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.  

It may help you and your family to meet with a genetic counselor and review your paternal family history in detail and discuss if the testing is appropriate.  As you know, you can find a genetic counselor through the NSGC’s website.  Best wishes to you in your studies!