The functional importance of the renin-angiotensin system is illustrated by several facts: by the severe neonatal complications observed in women treated with converting enzyme (ACE) inhibitors[129,130]; by the association of preeclampsia to autoantibodies to the Ang II type 1 receptor, and by the association of preeclampsia to the M235T polymorphism of the gene that codes for angiotensinogen[131,132]. This evidence concerns the gene REN and preeclampsia.