SNP genotyping and single locus association analysis
For further association analysis, all 5 SNPs identified in this study, plus one polymorphism in the promoter region (5'flankingSNP1;[33]) and four selected from the dbSNP database (in2SNP1, in3SNP1, in6SNP1, and in7SNP1), were genotyped with MSBE or ARMS (Table 1). All genotypes were in Hardy-Weinberg equilibrium (HWE), except for the G-347 T marker in the promoter region that had departure from the HWE in both controls (p = 0.024) and patients (p = 0.024). Genotype coverage was generally good and about 90% of the subjects were successfully typed.
All 10 SNPs were genotyped and have been analyzed by Fisher's exact test between the case and control groups. No association can be obtained between any of the TPH1 gene polymorphisms and BPD. The genotypic and allelic distributions of each marker are listed in Table 2.