Further processing of pri-miRNAs continues in the cell nucleus under the control of conserved RNase III Drosha and the DiGeorge Syndrome Critical Region Gene 8 (DGCR8) cofactor with the formation of a hairpin structure, 70–100 nucleotides in length, termed precursor miRNA (pre-miRNA). This evidence concerns the gene DROSHA and 22q11.2 deletion syndrome.