Personally I stick with allelic. I understand the meaning just fine, and learned it / figured it out within a few threads of reading when I was brand new.
I will never use the term "ALS" for anything other than the disease. I lost a very close relative to it in February and I can't say it without getting sad.
Also, I am seriously tired of everyone in the world "dumbing things down" put in a little effort and learn something new. /endrant