The analysis stratified by gender confirmed strong association of rs10459953 polymorphism in NOS2 gene with asthma showing significantly higher frequency of TT genotype and T allele among asthmatic boys (p = 0.00002 for genotypes, p = 0.000001 for alleles), but not in girls (p > 0.05) (data not shown). Here, NOS2 is linked to asthma.