HLA allele and haplotype associations in HFE C282Y carrying chromosomes of HH patients from three populations.

Comparisons between patients and controls were done using the Chi-square test (P values indicated) and the strength of the associations was estimated by the etiological fraction delta (δ).*HLA allele and haplotype frequencies in the controls populations from Porto (north Portugal) were obtained at the “Allele Frequencies in worldwide populations” database (Gonzalez-Galarza et al.(2011) Nucleic Acids Res 39∶913–919), from Alabama were reviewed from previous data reported by Barton et al. (2002) BMC Med Genet 3∶9; and from Norway were obtained in the study by Harbo et al. (2009) Tissue Antigens 75∶207–217.**Corrected allele and haplotype frequencies (see Methods) were calculated by subtracting from the denominator, respectively, the sum of A*03 and B*07 alleles and the number of A*03B*07 haplotypes.n.a. = data not available; ns = not significant.