Validation of small CNVs by real-time PCR. SYTO9 and primers specific to the DGCR6, PRODH, and TOP3B genes were used for detection in patients (P1–P20) and control genomic DNA samples (C1–C3). The normalized gene copy number is expected to be N = 2, compared with N < 1.5 for gene deletion and N > 2.5 for duplication. The bar graph shows a 50% decrease in copy number (Y-axis) of the DGCR6/PRODH gene for patient 1 and 2 and a 33% increase (from two to three copies) for patient 3 to patient 9 (P3–P9) compared with the control samples (C1–C3). The red bars indicate a gain of one copy number (duplication) of the TOP3B gene in 11 patients (P10–P20) compared with the control samples (C1–C3).