Not all auties (and/or) aspies are uber-intelligent.
There are also those who are not, yet who have a splinter-skill or skill group, particular unique talents that in many cases can be truly extraordinary. Many do not. Many of us, autie, aspie alike are simply US. Running different wetware certainly, and IMO a very desirable general operating system and CPU architecture, but that doesn't always mean its overclocked so hard there end up LN2 coolant pipes needing plugged in just behind the ears
And indeed, there does occur an autism phenotype that is comorbid with mental retardation. Apologies for not citing a source in the lit. But I am going from lifelong experience of almost exclusively my people to people interaction, online or in meatspace, being with other auties, and with aspies (and a girl with Rett syndrome, who in and of herself bucks the perception of RTT. Shes ambulant (a gym coach for special needs kids), EXTREMELY intelligent, obviously autistic-as-all-fuck, and an all round real good egg.
(not to mention I daresay, one SERIOUSLY, visual cortex-scorchingly sexy young lady

)
So theres a great deal of intrasyndromic variability.
I don't, however, quite understand, and never have, why parents think 'aspie=quirky and geek chic, good thing,, but Kanner's=shitty 'disease' or disorder.
I'd be delighted, if ever I have kids, if they turn out to be classically autistic, as I am. I think it would be quite a shame if they turned out to be neurotypical though, just because, there are so many ways of seeing the world, things either NT or spectrum phenotypes, miss. But I'd hate for my lil kid to be unable to for instance, walk in a forest at dawn, and have just the everyday textures, light plays, tiny life on the surface of a common, average, not at all showy plant, and be so captivated by these things, all interplayed, as to have tears of joy in their wonder rolling down their face, captivated in the moment.
Of something I'm 90% sure almost all NT would never even have noticed the leaves were there to begin with. And be totally blind to so many of nature's patternings.
To lack that (I refer to the pattern-perception, ofttimes highly synaesthetic) in exchange for the ability to pick up on social cuing, to NEED, and to suffer if deprived of, other human interaction, all the positives, and negatives aside of being eusocial, I could never trade. For me, it would be like having an eye torn out, to become numbed, sensorily stunted by the imposition of the filters in place that NTs have (and which benefit them by not having them constantly exposed to a whirling, screaming, chaotic in ways, yet on the otherhand often of breathtaking wonderment maelstrom of unprocessed raw datastreams) To have everything dampened by those sorts of filters...I can't imagine what that must be like.