LGI1 and early-onset autosomal dominant Alzheimer disease: This hypothesis is also supported by other gene‐wide associations reported in previous GWASs of Alzheimer's disease, such as MAPK7 (Nazarian, Yashin, & Kulminski, 2019) and APOC1 (Lo et al., 2019; Nazarian et al., 2019), and the functional mapping of LGI1, which was previously reported in relation to beta‐amyloid measurement in cerebrospinal fluid (Chung et al., 2018; Li et al., 2015), a biomarker for Alzheimer's disease (Blennow & Hampel, 2003; Frank et al., 2003; Sunderland et al., 2003).