SNP heritability analyses demonstrated that the collective effect of the measured SNPs accounted for 5% of the variance, or 10% of the heritability of ˜50%, as estimated from family-based studies. Recent GWAs on other complex traits such as height, BMI, and schizophrenia clearly demonstrated that with greater sample sizes the SNP h2 increases. The relatively small total GWAS discovery sample size (N=16,400), yielded limited power to detect small genetic effects which could partly explain the high "missing heritability" in our study, although we cannot rule out that most of the genetic variance in ASB is due to rare alleles. Taken together, we suspect that with greater sample sizes and better imputation and coverage of both the common and rare allele spectrum, over time, SNP heritability in ASB could approach the family-based estimates.
