normal variation by using the control data to define regions of the genome where dosage changes can be tolerated without overt phenotypic effects. Since non-recurrent CNVs are very rare events, the collection of data from hundreds of thousands of cases will be needed for this type of analysis to be successful. Continued efforts of the ISCA consortium, as well as other databases such as DECIPHER, will be essential to this process in order to obtain enough overlapping CNVs to provide the power needed for statistical analyses.
