 Targeted 1q21 array CGH investigation of the potential association between DUF1220 and brain size found that DUF1220 copy number decrease is associated with microcephaly in individuals with 1q21 CNVs.Of all 1q21 sequences tested, DUF1220 sequences were the only ones to show consistent correlation between copy number and brain size in both disease (micro/macrocephaly) and non-disease populations.In addition, in primates there is a significant correlation between DUF1220 copy number and both brain size and brain cortical neuron number.