ABCG2 and Down syndrome: Various pregnancy conditions and complications present altered DNA methylation level in the placenta, including obesity, maternal diabetes (Reichetzeder et al., 2016; Lizárraga et al., 2024; Hjort et al., 2022), preeclampsia (Cruz et al., 2020), caesarean section (Słabuszewska-Jóźwiak et al., 2020), down syndrome (Jin et al., 2013) or large for gestational age (Dwi Putra et al., 2020), and several of these conditions have been linked with placental ABC transporter expression alterations (Kozlosky et al., 2022).