Supplemental Figure S4.

Comparison of the sensitivity between AmplideX-C9 and Penn-C9 in detecting the C9orf72 expansion using formalin-fixed, paraffin-embedded (FFPE) DNA. Genomic DNA was extracted from paired fresh-frozen brain and FFPE tissue from 10 representative cases carrying the C9orf72 expansion. Allele sizes for each case are indicated in the parentheses. Expansions without sequence variation (exp), with an insertion (exp^ins), or with a deletion (exp^del) are noted. All samples were tested with AmplideX-C9 (A) and Penn-C9 repeat-primed PCR assays (B). The result for the fresh-frozen brain for Penn-C9 is not shown, but all had the expected saw-tooth pattern for a C9orf72 expansion. Genotypes, with the number of repeats on the normal allele, are indicated for each case on the left. The result interpretation for each FFPE electropherogram is indicated: expansion (EXP), false negative (False neg), indeterminate (IND), or no amplification (failed).