Large-Scale Exome Sequencing Study Implicates Both Developmental and Functional Changes in the Neurobiology of Autism cell.com/cell/fulltext/… - yet more evidence for importance of rare mutations in autism 
Mutations in over 100 genes now strongly linked to autism and other neurodevelopmental disorders (not including already known syndromic forms, like Fragile X, Rett syndrome, copy number variants, etc...)
Note that this paper was only looking for "de novo" mutations - ones that arise in the generation of sperm or egg, which can explain sporadic cases of neurodevelopmental disorders...
There are also inherited mutations that explain why these conditions often affect multiple children in a family, as discussed here: The genetic architecture of neurodevelopmental disorders biorxiv.org/content/10.110…
"Autism" is thus an umbrella term for hundreds of distinct (and individually complex) genetic conditions that can result in those symptoms or others
With sequencing efforts like the one in this paper, we are moving more and more cases from the "idiopathic" pool to ones with a known major genetic contributor
The genes implicated also support the neurodevelopmental origins of the condition, with high expression in fetal cortex...
... and enrichment for genes controlling gene expression or neuronal communication - key functions in genomically driven and activity-dependent neuronal development
The current paper also confirms the "female protective effect" - it takes a bigger genetic insult to push the developing female brain into one of these clinical states
