S1.

The complete data structure of genetic polymorphism study

Genotype amount
Genotype type	AA	AB	BB
AA:Wild homozygous AB: Heterozygous mutant BB: Mutant homozygous n: indicating the Nth study. For a SNP, two alleles, A and B, could be presented. Specifically, A was considered as wild type, meanwhile, B was considered mutant type. Therefore, there may be three genotypes, AA, AB, BB, respectively, in population. Suppose there were three genotypes of the subjects, we could assign a, b, c to AA, AB, BB in case group, and d, e, f to AA, AB, BB in control group, respectively. The table above could offer additional explanation. In meta-analysis for SNPs, polygenic model was used to decrease probabilities of type I error. The following genetic models may be used in our study: 1) Additive model (i.e. B vs. A); 2) Dominant model (BB+BA vs. AA); 3) Recessive model (BB vs. BA+AA); 4) Homozygous model (BB vs. AA). Specifically, the additive model was used first, and the rest models were also used when additive model was not usable.
Case group	an	bn	cn
Control group	dn	en	fn