If you have low muscle tone in your mouth and throat, you could have sleep apnea, which runs on my husband's side. But low tone could occur in different areas of the body, so you won't see it in all aspies, and not all in the same place. But if you have any speech oddities or pronunciation problems, plus sleep problems, you might look into that.
Also from what I have been noticing with a lot of the spectrum kids I know is that low tone in the abdominal muscles causes digestive problems.
I believe digestive problems are also related to allergies, because the GFCF diet seems to help alleviate allergies for us, and a lot of these kids seem to have lots of allergies.
I also read somewhere that a very high percentage of spectrum children also have seizures.