I don't believe in deities, but from a theist's point of view, God is omnipotent, omniscient and omnipresent. Nothing happens without his knowledge and permission. therefore, if you believe in God, you should believe he created Asperger's, cancer, incontinence, hemorrhoids, accents and everything else that was mentioned in this topic.
But I prefer more reasonable explanations. I will stick with evolution, at least for now. Supposedly, there is a genetic factor on ASDs, implying mutation. Since it's been happening for some time now (and, from what I've on the internet, it's been increasing over time), we can assume autistic individuals have been passing their genes, indicating that the mutation is at least partially beneficial. In other words, microevolution.