Guidelines and Guidance Systematic Reviews of Genetic Association Studies

The past decade has witnessed growing interest in genetic predisposition to common diseases, and along with rapid advancements in high-throughput genotyping technology, has resulted in a tremendous amount of published epidemiological evidence on gene-disease associations. Reported genetic associations with common diseases have become numerous and are mostly of small magnitude [1]. With this growth in evidence has come an increasing need to collate and summarize the evidence in order to identify true genetic associations among the large volume of false positives [2]. Convincing evidence of true association therefore requires careful control over potential biases and chance effects. Control over bias is important both in study design [3] and in considering the selective availability of data on associations that have been examined [4]. Because most genetic associations are small, large sample sizes are necessary for their detection, especially whe