Figure 3. Example of an MLPA copy number assay. Raw fluorescent intensity (y-axis, relative fluorescence units) observed during capillary electrophoresis are illustrated. The first peak represents the amplicon of CFH intron 1 with a product size of 100 bp (x-axis, bp), followed by the other probes as illustrated. The ratio of peak height of all probes to SS18 determines the copy number (see methods). CFHR2 always has a high peak, which is taken into account with normalization. Therefore, this does not show a duplication of CFHR2. Panel A shows a wild-type subject, panel B a subject heterozygous for deletion of both CFHR3 and CFHR1, and panel C a subject homozygous for deletion of both CFHR3 and CFHR1. The X-chromosome marker (PDCD8) shows that all three subjects are females.