The vaccine hypothesis has some problems to explain, and as of yet is lacking evidence. Some of the problems, monozygotic twins have a concordance of 60-90%, while dizygotic twins show a concordance of only 5-10%. This follows that autism is a highly heritable trait.
Other problems, the ratio of male to females with autism is about 4:1. Some recent studies have found that mutations in sperm cells can cause autism without the parents having the disease. It's identified by the deletion of the neurexin 1 gene. And now there is a study suggesting that the protein CADPS2, a protein found in one region of chromosome 7, might predispose individuals to autism. An Abnormal form of the CADPS2 mRNA has been found in those with autism, but not as high in prevalence in their relatives.
So, maybe it's a polygenic trait. There seems to be good evidence for that hypothesis rather than a simply inherited trait.
Other problems, the ratio of male to females with autism is about 4:1. Some recent studies have found that mutations in sperm cells can cause autism without the parents having the disease. It's identified by the deletion of the neurexin 1 gene. And now there is a study suggesting that the protein CADPS2, a protein found in one region of chromosome 7, might predispose individuals to autism. An Abnormal form of the CADPS2 mRNA has been found in those with autism, but not as high in prevalence in their relatives.
So, maybe it's a polygenic trait. There seems to be good evidence for that hypothesis rather than a simply inherited trait.