Combined analysis using directly genotyped data for Stages 1 and 2 revealed that rs1406714 in CHD2 was associated with decreased risk of NOA [odds ratio (OR) = 0.78, 95% confidence interval (CI) = 0.68-0.89, Pmeta = 1.7E-04], whereas rs2126986 in GNAO1 and rs7226979 in BCL2 were both risk makers for NOA (rs2126986: OR = 1.28, 95% CI = 1.15-1.41, Pmeta = 2.3E-06; rs7226979: OR = 1.21, 95% CI = 1.11-1.33, Pmeta = 4.5E-05).