FIGURE 2.

Quantification of C‐ and N‐terminal TDP‐43 peptides in motor and prefrontal cortex urea fractions by MS‐PRM discriminates ALS from other neurodegenerative diseases. (A and B) Shown are absolute abundances of light peptides (log₁₀ ratio (light:heavy peptide)) (A) The N‐terminal peptide was decreased in ALS (n = 16) compared to AD (n = 8) (**p = 0.001), but not in ALS compared to CTL (n = 8) and PD (n = 8) (p = 0.13 and p = 0.051). (B) The C‐terminal peptide was increased in ALS compared to PD (**p = 0.0045), but not in ALS compared to AD and CTL (p = 0.7, p = 0.29). (C) The calculated C:N‐terminal peptide ratio was increased in ALS compared to AD, PD, and CTL (****p < 0.0001 respectively). One‐way ANOVA with Dunnett’s multiple comparison test. (D) ROC curves of N‐terminal and C‐terminal peptide abundances and the calculated C:N‐terminal peptide ratios for discrimination between ALS and CTL, PD or AD. For comparison, the AUCs are shown