Similarly, PCA using most the 12 most differentially abundant proteins (C2 CD5, CHI3L1, CHIT1, SLC39 A10, XXYLT1, TGFBR3, SORCS3, HYOU1, MINPP1, CHI3L2, SERPINA3, and PCDH11X) effectively distinguished asymptomatic from symptomatic ALS individuals (Fig. 7b). Here, PCDH11X is linked to amyotrophic lateral sclerosis.