Table 2.

Increased frequency of de novo CNVs in autism. The numbers of de novo events are listed for our autism sample and for each category of family separately (simplex, multiplex, and nonautism control). The difference between cases and controls was examined, and the statistical significance was determined using Pearson’s chi-square test with simulated P value from 2000 replicates. The P value for the difference in frequency between cases from simplex and multiplex families was also determined.

Sample group	n	CNVs de novo	Ratio	P value
				χ2	Multiplex/simplex
Simplex autism	118	12	0.102	0.0005	0.043
Multiplex autism	77	2	0.026	0.59
Simplex + multiplex	195	14	0.072	0.0035
Controls	196	2	0.010