A significant association between the C allele, PTPRS “high”, and AD risk reduction in the genetically homogeneous Quebec Founding population (QFP) isolate from Eastern Canada (p = 0.02, OR 0.86) and in the larger heterogeneous IGAP II GWAS (p = 0.01, OR 0.97) was observed (Table 1). This evidence concerns the gene PTPRS and Alzheimer disease.