Given prior evidence for the contribution of rare copy number variations (CNVs) to autism
spectrum disorders (ASD), we studied these events in 4,457 individuals from 1,174 simplex
families, composed of parents, a proband and, in most kindreds, an unaffected sibling. We
find significant association of ASD with de novo duplications of 7q11. 23, where the
reciprocal deletion causes Williams-Beuren syndrome, featuring a highly social personality.
We identify rare recurrent de novo CNVs at five additional regions including two novel ASD�…

To explore the genetic contribution to autistic spectrum disorders (ASDs), we have studied
genomic copy-number variation in a large cohort of families with a single affected child and
at least one unaffected sibling. We confirm a major contribution from de novo deletions and
duplications but also find evidence of a role for inherited" ultrarare" duplications. Our results
show that, relative to males, females have greater resistance to autism from genetic causes,
which raises the question of the fate of female carriers. By analysis of the proportion and�…