Familial ALS

I am a 40 year old female.  My dad passed away in 1997 at age 60 from ALS that began with his speech and progressed from there over 7 years.  Based on current data, what are the odds that ALS could be familial in a family with a history such as mine?  My dad's brother died from a gunshot wound in his late 30's; his sister is still living and healthy at age 63; his mom passed away from natural causes in 2000 at the age of 84; his dad died from a heart attack at age 50 (very heavy smoker).  Both sets of grandparents died in their 70's and 80's.  I don't have any symptoms but am just curious as I have to sons to worry about.  Thank you for this forum and your time.

[CCF-Neuro-M.D.-CS]

Approximately 5-10% of all cases of ALS are inherited (passed from one generation to the next).

In 20% of the inherited type the genetic mutation is known (superoxide dismutase-1) and it is inherited from generation to generation in an 'autosomal dominant' fashion - this means that, in this rare form of ALS,  if one parent is affected, there is a 50% chance that a child will be affected.

in the other 80% (of inherited ALS) the cause is unknown, and therefore the inheritance pattern in unknown, although a lot of research is being done in this area.

If only one family member is affected, the odds are very stacked in your favor that the disease will not be inherited