Similar to the Dab1 gene, the Reelin gene is also known to exhibit haploinsufficiency (Liu et al., 2001; Carboni et al., 2004; Qiu et al., 2006; Nullmeier et al., 2011; Bouamrane et al., 2016; L. Wang et al., 2019), and reduced Reelin levels have been observed in the brains of patients with schizophrenia (Impagnatiello et al., 1998; Guidotti et al., 2000), bipolar disorder (Guidotti et al., 2000), autism (Fatemi et al., 2001, 2005), and Alzheimer’s disease (Chin et al., 2007). Here, RELN is linked to early-onset autosomal dominant Alzheimer disease.