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. Here, PSEN1 is linked to Alzheimer disease.