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). The gene discussed is CHIT1; the disease is amyotrophic lateral sclerosis.