The regression model adjusted for age and sex, analyzing YKL-40 levels in plasma, did not reveal significant differences between the control group (control: 173.32 ± 11.39 ng/mL) and the non-treated adult SMA patient samples (SMA(Pre): 88.16 ± 6.50 ng/mL) due to the group effect [F(1,55) = 1.474, p = 0.230]. Here, CHI3L1 is linked to proximal spinal muscular atrophy.