SAMHD1 and early-onset autosomal dominant Alzheimer disease: In this study, since C. elegans has been extensively explored as animal models for various human diseases including Parkinson’s disease (57) and Alzheimer's disease (58), we explored a series of biochemical and structural validations of ZK177.8 SAMHD1 ortholog, which is required for its potential as a model for the SAMHD1-related human disorders.