Reading comprehension has never been my strong suit so forgive me if I am misinterpreting... Are you asking if it's possible for
ALS to skip a generation? If that is your question then the answer is yes. My mother died from
ALS though her mother never developed the disease, it came from her mother's mother, my mother's grandmother.
We thought the disease had died out in a sense but it reappeared suddenly about a year ago. You can be passed the gene that carriers the
ALS but not develop symptoms of the disease thus being able to pass it to your children without having the disease yourself.