These techniques have helped identify genetic influences that vary from low risk (e.g., CR1, CD33, CD2AP, etc.), to medium risk (e.g., ADAM12, PLD3, ABCA7, etc.), high risk (e.g., APOE, TREM2 and SORL1, etc.)and causal (e.g., APP, PS1 and PS2) associations with AD. This evidence concerns the gene PSEN2 and Alzheimer disease.