followed by 65 cycles of at 95°C for 15 sec and 60°C for 1 min. Amplification was performed on PTC-200 cyclers (MJ Research, Hercules, CA) and data were analyzed using the ABI Prism 7900HT Sequence Detector System and software version 2.1 (Applied Biosystems, Foster City, CA). All samples were run in duplicate for quality control purposes; discordant genotypes were discarded. In family and unrelated samples, 15 SNPs (including rs4680, genotyped by both methods) were genotyped by means of a customized Golden Gate SNP array (Illumina, San Diego, CA). For general quality control for this array, 11.5% of all samples were genotyped in duplicate, with no mismatches observed between the two assessments. Based on comparison of the duplicate runs (TaqMan 5′ nuclease and Illumina array genotyping) in 1586 samples, the mismatch rate for rs4680 was 0.19%.
