This is the third such study published within this year. The difference being that this study did full genome sequencing rather than exome (regions coding for proteins) sequencing.

The other papers: O'Roak BJ, et al. Sporadic autism exomes reveal a highly interconnected protein network of de novo mutations. Nature. 2012

Sanders JS, et al. De novo mutations revealed by whole-exome sequencing are strongly associated with autism. Nature. 2012