Clinically, in addition to increased risks of a variety of birth defects from the presence of the T allele (Pi et al., 2020), is also associated with higher risks of schizophrenia (Lewis et al., 2005), male infertility (Karimian and Colagar, 2016; Aliakbari et al., 2020), gestational diabetes (Tan and Chen, 2023) and recurrent pregnancy loss (Wu et al., 2012) in Asians, and Alzheimer’s disease in Asians (Hua et al., 2011; Peng et al., 2014) and APOE4 carriers (Peng et al., 2014). The gene discussed is APOE; the disease is Alzheimer disease.