Many studies have reported that TTR tend to be lower in female patients than in male patients with AF (Gomberg et al., 2006; Sullivan et al., 2012; Arbring et al., 2013; Tomita et al., 2013; Abohelaika et al., 2016; García-Sempere et al., 2019). The gene discussed is TTR; the disease is atrial fibrillation.