In one of our studied cases (retinal degeneration and Pde6b), the causative haplotype block was much more strongly associated with the phenotypic response pattern (genetic association p-value = 0) than with population sub-structure (PS p-value = 0.024), but in another case (HDL levels and Apoa2), the p-values for the causative haplotype block were of a similar magnitude. Here, APOA2 is linked to retinal degeneration.