Marker information and related summary statistics are presented in Table 2. For each SNP, the genotyping rate was >95% and the genotype distribution in the control sample was consistent with HWE. However, three SNPs (rs2236196, rs1044394, rs6010918) in ND cases and four SNPs (rs2236196, rs3787138, rs1044394, rs6010918) in FTND cases had genotype distributions that were not in HWE (0.004 < P < 0.05). Considering all the SNPs are in HWE in control samples, we included all the SNPs for association tests in subsequent analysis. In addition, there were large differences in allele frequencies between EAs and AAs for each SNP tested. Therefore, to avoid the spurious associations that can arise from stratification in the analysis of the combined sample, race was included as a categorical covariate in the association test.
