AGPAT1 and early-onset autosomal dominant Alzheimer disease: One SNP near AGPAT1 demonstrated a negative allelic effect between frontotemporal dementia, which exhibits parkinsonism and related pathology, and (immune-mediated) celiac disease; another SNP has been associated with Alzheimer’s disease (Agarwal et al., 2017; Broce et al., 2018; Rowe, 2019).