This replication, in African-Americans, of the rs16969968 association adds crucial information because of the different LD and population history for African-Americans, and because of the much lower allele frequency of rs16969968 in this population. The allele “A” at rs16969968 is rare in African-Americans, with a frequency of 5% (6% in cases, 3% in controls), compared to 35% in European-Americans (39% in cases, 31% in controls), and it is not present in the HapMap YRI. Nonetheless, it is a risk factor in our sample of African descent. The odds ratio is 2.04 (1.15–3.62) in African-Americans and 1.40 (1.23–1.59) in European-Americans. These confidence intervals overlap, and the ORs are not significantly different in the two populations (heterogeneity p = 0.24). Thus the “A” allele at rs16969968 is a consistent risk factor in both populations. Furthermore, in each group rs16969968 is the most significant and has the highest odds ratio.
