Both genome-wide linkage and GWAS are considered “unbiased” exploratory approaches. By comparing their results, we found that only two GWS signals are within the nominated linkage peaks, which are LOC100188947 and BDNF.34, 140 The other nine loci, including the three most replicable ones, are all outside of the linkage peaks, and the rest of the 12 linkage regions do not contain any GWS signal (Tables 1 and 2). This discrepancy might reflect not only the different natures of the two genome-wide approaches but also different ND measures used among those studies. Genome-wide linkage studies usually investigate sparse microsatellites segregated with the trait of interest in different families, whereas GWAS takes advantage of dense common variants and thousands of unrelated individuals. Because of the distinct characteristics of family and case control samples and known locus heterogeneity for ND, we might not expect same sets of susceptibility alleles to be detected by both approaches. The relatively large nominated linkage regions tagged by microsatellites may implicate common or rare variants or both within the region of interest, on the other hand, it is
