Among the most relevant neuroinflammatory markers, chitinases, particularly chitotriosidase (CHIT-1) and chitinase-3-like protein 1 (CHI3L1/YKL-40), are secreted by activated microglia and astrocytes and have been identified as cerebrospinal fluid biomarkers of neurodegeneration in adults with DS [59,60]. The gene discussed is CHI3L1; the disease is Dravet syndrome.