Pairwise linkage disequilibrium (LD) structure and 11 SNPs of the NOS1 gene. Panel (A) represents children with normal endothelial function (NEF), and Panel (B) represents children with endothelial dysfunction (ED). The plot was generated using Haploview 4.2 with D’ Color Scheme (D’ = 0, D’ < 1 and D’ = 1 shown by white, shades of pink and red (respectively) and pairwise r2 values shown in diamonds. The value within each diamond represents the pair-wise LD (correlation, measured as D’) between the two SNPs defined by the top left and the top right of the diamond. Solid lines represent SNPs that were used in the haplotype analysis, and are part of the haplotype from SNP block whereas dashed lines represent SNPs that were used in the analysis, but were not part of the haplotype.