As compared to control group, SCD late menarche group (Table 1) had significantly higher prevalence of heterozygous genotypes, 4a/4b of eNOS 4a/b, G/T of eNOS 894G>T, T/C of eNOS - 786T>C along with higher frequencies of mutant alleles ‘4a. The gene discussed is NOS3; the disease is Schnyder corneal dystrophy.