The geographical distribution of positive and negative gene association data in Alzheimer's disease and schizophrenia

If there is one factor common to genetic association studies it is their heterogeneity Bertram and Tanzi 2004 Shi et al, 2008 Dozen of confusing positive and negative studies blur the picture and suggest that many are related to artefact or insufficient statistical power. However, while at a global level these results are contentious, at a local level they can be quite homogenous, tending to cluster in positive or negative association hot and coldspots around the world.These examples are taken from data from the Alzgene and Szgene databases and are posted to illustrate this phenomenon.