Figure 1.
The graph represents the general relationship between allele frequency (X-axis) and effect size (Y- axis). The top dotted curve shows the anticipated relationship prior to the advent of genome wide approaches to association and the bottom curve the shift attending empirical data regarding the odds ratios found in the majority of common variant studies. The blue box highlights the region into which recent rare variant findings in ASD fall, representing low frequency alleles but carrying risks that are not of the scale identifed in rare Mendelian disorders. The red arrow at the top of the diagram represents the shift toward association that is required to identify alleles that are neither necessary nor sufficient (either within a given pedigree or the general population) for the emergence of a phenotype