NOS3 and erectile dysfunction: The NOS3 (rs2070744) polymorphism, which results from the nucleotide substitution of thymine by cytosine (T/C) at position -786, has been associated with a reduction in the expression of eNOS, and is clinically linked to vascular disorders such as myocardial infarction, angina, atherothrombosis, erectile dysfunction, stroke and kidney disease [8, 9, 47–50].