We completed a dense SNP genomewide linkage scan for the trait of DSM-IV AD in a sample of AA small nuclear families. We observed one genomewide significant linkage result, on chromosome 10, at 117.4 cM. Although we observed other linkage signals that might indicate locations of AD susceptibility genes, most notably a lod score of 1.67 on chromosome 17, the chromosome 10 signal was by far the strongest and the only one meeting genome wide significance. This is the first report of genomewide-significant linkage to the trait of AD in an AA population, and the first report of a significant AD linkage to this chromosomal location, to our knowledge. Li et al. (34) have previously reported on a linkage study for nicotine dependence-related traits in AAs, and they, interestingly, also reported a single genomewide-significant linkage signal, also on chromosome 10. These investigators observed a lod score of 4.17 at 92 cM. Because this location is not within the 1-lod support interval for the locus we observed on the same chromosome, it likely represents a different risk gene. We previously reported
