Figure 6.

Mosaicism of the expansion allele pattern. The repeat-primed peak patterns for AmplideX-C9 (A) and Penn-C9 repeat-primed PCR (RP-PCR) assays (B) for two samples. One (ND005) demonstrates a typical saw-tooth peak pattern for both assays, whereas the pattern for ND006 demonstrates a heterogeneous expansion peak pattern (red arrows) with the AmplideX-C9 assay suggestive of mosaicism of the C9orf72 expansion, which is not observed with the Penn-C9 assay. The view of the x axis for ND006 is zoomed in on the bottom row, showing additional peaks between each repeat peak. Red lines indicate off-scale peaks. This heterogeneous expansion peak pattern is not obvious with the Penn-C9 assay. 2/exp, 2 repeats and expansion; 4/exp, 4 repeats and expansion.