Numerous reports have been made of the association between serum and plasma NfL and the severity of acute central nervous system injury, as well as the presence and state of neurodegenerative disease, including AD in humans (Preische et al., 2019; Ashton et al., 2019), AD rodent models (Bacioglu et al., 2016; Andersson et al., 2020), and cognitive dysfunction in dogs (Panek et al., 2020). This evidence concerns the gene NEFL and Alzheimer disease.