In contrast, the analyses for AD-only (case-control) gave rise to significant global haplotypic association only in A3-A6, D1-D3, A7-D3, and N12-N16 (p = 0.04 to 0.0037; Table 2); however, no specific individual haplotype was significant. The association analysis for AD+DD in the family sample (Table 3) showed that global haplotypes were significantly associated in the three risk or protective regions, NCAM1 exon 12, TTC12 exon 3 and the junction of ANKK1 and DRD2, corroborating those identified in the global association analysis of AD+DD in the case-control sample. There were small differences for these AD+DD association findings between the family and the case-control samples in terms of the statistical significance level, the number of significant haplotypes, and the extent to which the haplotypes extended along the chromosome in the three regions (compare Table 2 with Table 3). These differences could be due to lower statistical power associated with the family study design, a relatively small sample size in that study, and sampling variation, among other possible explanations.
