We found that the nephropathy group exhibited the highest mean serum cystatin C level, which was higher (though not statistically significant) than that of the HC (p = 0.15), ALS (p = 0.15), Alzheimer’s (p = 0.15) and Parkinson’s (p = 0.31) groups (Figure 17A). Here, CST3 is linked to amyotrophic lateral sclerosis.