In adults with DS, low CSF NPTX2 levels were associated with low CSF Aβ1–42 (r2 > 0.3, p < 0.006), low CSF t-tau (r2 > 0.3, p < 0.001), increased cortical atrophy (p < 0.05) and reduced glucose metabolism (p < 0.05). The gene discussed is NPTX2; the disease is Dravet syndrome.