Overview of Genome Wide Association Studies and study designs

The second of a series of seven online lectures for Genome Wide Association Studies (GWAS) will provide a basic overview on genome-wide association studies (GWAS). This is timely with the H3Africa genotyping data becoming available for several of the H3Africa research groups. To enable genomic research, the H3Africa Consortium had to build some of its own resources. This has involved sequencing whole genomes from selected under-represented African populations, analyzing the data to identify common genetic variation across major groups and developing a unique GWAS array, enriched for common African variation. The H3Africa SNP genotyping array, is currently the best-suited array available for African genome-wide association studies.

What does it take to develop a genome study to understand genetic and environmental contributions to complex disease traits? This GWAS lecture will cover the research process from protocol development to data quality control and GWAS analysis approaches. It will include the two main study designs:

Case : control (e.g. diabetes, hypertension, kidney disease)
Continuous trait (e.g. LDL-Cholesterol, body mass index, height) GWAS.

I will discuss the basic building blocks of a GWAS study, the different study designs, power of a study to detect genetic association (based in sample size, allele frequency and expected effect size), and replication studies. The advantages and disadvantages of doing GWAS in African populations will be discussed.