NOS3 and Schnyder corneal dystrophy: Our data indicates that heterozygous carriers of eNOS gene polymorphism particularly eNOS 4a/4b has 13.9 fold, eNOS 894G>T G/T has 11.5 fold, eNOS -786T>C T/C has 14 fold higher risk of late onset of menarche in SCD females as compared to control groups.