ENO2 and early-onset autosomal dominant Alzheimer disease: Circulating NSE levels were higher in symptomatic Huntington' disease (Ciancarelli et al., 2015), and CSF (Schmidt et al., 2014) but not circulating (Chaves et al., 2010) NSE levels were elevated in Alzheimer's disease, whereas the NSE literature in Parkinsonian syndromes is conflicting (Constantinescu, Zetterberg, Holmberg, & Rosengren, 2009; Schaf et al., 2005).