CHI3L1 and Duchenne muscular dystrophy: Some skeletal muscle gene expression profiles for DMD patients have also shown CHI3L1 to be up-regulated compared to healthy controls [8, 10, 43], and at least one mdx expression profile has shown a slight increase in the murine homolog to CHI3L1, Chil1, in the skeletal muscle of mdx compared to control mice [88].