HMGCS2 has been suggested to play important roles in diabetes, tumor, Alzheimer's disease, and intestinal cell differentiation (Wan et al, 2018, 2019; Cheng et al, 2019; Kim et al, 2019; Zou et al, 2019; Wang et al, 2019b). This evidence concerns the gene HMGCS2 and early-onset autosomal dominant Alzheimer disease.