The potential of common CNVs has until recently (11,26) been largely neglected despite the fact that power issues to detect common CNVs will be less extreme when compared with rare CNVs. The main reason might be that samples have often been genotyped by arrays not designed for the detection of common CNVs. As an example, following recent reports (13), 44% of the common CNVs detectable by the more recent Affymetrix Genome-Wide Human SNP Array 6.0 would not have been detected by a previous Affymetrix chip (Affymetrix 500K Mapping Array Set).
