A recent study has specifically investigated whether cystatin C content in ALS CSF (measured by ELISA) could serve as a disease biomarker: the authors describe a correlation between lower Cystatin C levels and shorter survival times as well as significantly reduced levels in ALS patients in comparison to healthy controls but not to CSF from patients with other neurological disorders, again highlighting the benefit of biomarker panels consisting of several differentially regulated peptides [12]. The gene discussed is CST3; the disease is amyotrophic lateral sclerosis.