MLPA analysis of the F8 gene in 4 members of family A.F8 MLPA profiles are shown for 2 males with high and normal FVIII levels, respectively (left) and 2 females with high and normal FVIII levels, respectively (right), coded as in Figure 1. The peak obtained for each F8-specific probe was normalized against the average of the peaks of the reference probes in the same DNA sample, and the peak ratio was plotted as a function of the corresponding F8 exon. A peak ratio of ∼1.0 indicates a normal number of copies (1 for males, 2 for females), whereas peak ratios of ∼2.0 (in males) or ∼1.5 (in females) indicate a duplication of the sequence recognized by that probe. Note that some F8 exons, including exon 1, are targeted by >1 probe.