Naturally, the real report doesn't "reveal" any such link; though it strongly suggests one: propionic acid (PPA).
Executive Summary: autistic children have mitochondrial disease or some biomarkers compatible with it at a rate higher than the general population. Something like autism can be induced in rats infused with PPA. Surveys of autistic and neurotypical youngsters showed fatty acid concentrations that were abnormal, somewhat (not entirely!--their figure 1 has a logarithmic concentration scale and symmetric error bars? and isn't easy to compare) like that in the rats.
Autistic youth typically seem to have a different mix of gut flora than normal, more of which produce PPA, some of which will presumably go into the bloodstream and help disrupt mitochondrial activity. (BTW, antibiotics change the gut flora mix, apparently increasing the proportion of PPA-makers.)
So, since O(17%) of children with ASD apparently had abnormal mitochondrial fatty-acid metabolism (like those rats with pseudo-autism), and some of them showed no genetic abnormalities to account for it, some subset of autism is possibly due to (internal) environmental disruption of mitochondrial activity.
End Executive Summary.
It isn't clear that this is fixable after the fact, though it would be wonderful if it were (assuming this is actually the issue).
But notice the number 17%. We use the term "autism spectrum" but apparently there are quite a few different genes involved: 15 according to the notes in this paper.
That second paper is worth a look too. The authors looked at copper and zinc levels (copper levels are high in autism spectrum children relative to neurotypical children, zinc levels low in autism and PDD (but not Aspergers). They applied a B6 and zinc supplement therapy, and found changes to more normal levels in autistic and PDD children, and apparent improvement in behavior--but not in Aspergers children. (I didn't see where there was any medium-term follow-through to see if there really was improvement.)
I call this sort of thing evidence that the phrase "autism spectrum" is a misnomer. "Autism constellation" would be a better term, since it looks as though there are multiple causes with similar effects.
Which is kind of discouraging when you want to know "What should I do for my kid?"