Glucose transporter 2 (GLUT2) is a transmembrane carrier protein that enables passive glucose movement across cell membranes. It is the principal transporter for transfer of glucose between liver and blood, and for renal glucose reabsorption. In humans, this protein is encoded by the SLC2A2 gene.It has been proposed by genetics researchers in neonatal and maternal-fetal medicine at Harvard University Medical School and Beth-Israel Deaconess Hospital Medical Center, that this creates a problem for drug treated diabetic pregnancies in which glucose levels in the woman are uncontrolled, exposing her fetus to the possibility of neural tube and cardiac defects in the early-developing brain, spine, and heart.