2 (p = 0.001). Our approach to assessing the genome-wide significance of rare recurrent de novo events provides for a statistical evaluation of CNVs observed in cases without requiring additional matched control samples. Consequently, we were able

to conduct a cumulative analysis across multiple studies in search of additional associated ASD loci. We included four other large-scale ASD CNV studies (Itsara et al., 2010, Marshall et al., 2008, Pinto et al., 2010 and Sebat et al., 2007) meeting four criteria: standardized diagnosis, genome-wide detection, confirmed de novo structural variations, and sufficient information to permit the identification of duplicate samples. These data sets cataloged 219 confirmed rare de novo CNVs from a total of 3816 individuals (Table S1). We found six regions that exceeded the threshold for significance (Experimental Procedures). Given prior evidence and our own data suggesting that reciprocal deletions and duplications Selleckchem BYL719 at the same locus may both contribute to the ASD phenotype, we evaluated significance for combined events at every interval and calculated probabilities for deletions and duplications

separately (Table 4 and Figure S3). The most frequent recurrent de novo CNV identified across all studies was 16p11.2 with 19 identified probands (14 deletions, 5 duplications) showing extremely strong evidence for association with ASD (2 × 10−55 combined, 5 × 10−29 for deletions, and 2 × 10−5 for duplications). The proximal long arm of chromosome 15 showed two contiguous www.selleckchem.com/products/epacadostat-incb024360.html intervals; the first corresponds to the region 15q11.2-13.1 or BP2-BP3 (seven duplications, 4 × 10−9) (Figure 7A), long cited as the most common cytogenetic abnormality identified in idiopathic ASD (Cook et al., 1997). We also found evidence of association for the interval enough mapping to 15q13.2-13.3 or BP4-BP5 (five duplications and one deletion; 1 × 10−4 combined, 2 × 10−5 for duplications) (Figure 7B). Rare deletions and duplications in this region have previously been associated with intellectual disability and ASD and deletions have been associated with schizophrenia and epilepsy (Figure 7). It is important to note, however,

that considering only events restricted to 15q13.2-13.3 (i.e., removing three overlapping isodicentric chromosome 15 events) resulted in a loss of statistical significance (0.53 combined, 0.88 for duplications). This suggests either that the result is an incidental finding because of the proximity to a true ASD risk locus or, alternatively, that the smaller 15q13.2-13.3 CNVs might point to a minimum region of overlap mapping to one or more ASD-related genes. Recurrent de novo CNVs exceeding the significance threshold in the combined sample were also present at 7q11.23 (four duplications, 0.003), in the 22q11.2 region (three deletions and two duplications, 0.002 combined; 0.11 for deletions; 0.88 for duplications), and at the locus coding for the gene NRXN1.