Relative predispositional effect: the overall frequency distribution of all haplotypes at the DRB1-DQB1 loci in MS patients (n = 2,555) compared with the distribution in controls (N = 1,365).

<p>DRB1-DQB1 haplotypes in MS patients (col.1), the number observed (col. 2) and expected from controls on the basis of the assumption that there were no differential predispositional effects on the DRB1-DQB1 haplotypes (col. 3), and the contribution of each haplotype to the overall <b>χ</b>2 (col.4). The overall <b>χ</b>2 distribution was considered statistically significant at P<0.001 (col. 5).</p><p>Rare haplotypes belonging to the same haplogroup were grouped together: as *04 were designed *04∶01-*03∶01-*03∶02, *04∶02-*03∶02, *04∶03– *03∶01-02-04-05, *04∶04-*03∶02-*04∶02, *04∶05-*02∶01, *04∶05-*03∶02, *04∶06-*03∶02, *04∶07-*03∶01 and *04∶08-*03∶01; as *08 were designed *08∶01-*03∶01-*04∶02, *08∶03-*03∶01 and *08∶04-*03∶01-*04∶02.