Which gene is associated with the early onset form of Alzheimer’s Disease?

The gene PSEN1 (Presenilin 1) is known to be associated with early onset familial Alzheimer's disease, which typically manifests before the age of 65. Mutations in the PSEN1 gene are responsible for the majority of early onset forms of Alzheimer’s, leading to the production of abnormal proteins that disrupt normal cellular function and contribute to neurodegeneration.

PSEN1 is part of a complex involved in the cleavage of amyloid precursor protein (APP), a key player in the pathology of Alzheimer's disease. The improper processing of APP can lead to the accumulation of amyloid-beta peptides, which form plaques in the brain—one of the hallmark features of Alzheimer’s.

The other genes listed do not have established connections to early onset Alzheimer's disease. SOD1 is primarily linked to amyotrophic lateral sclerosis (ALS), KCNQ1 relates to cardiac arrhythmias, and RYR2 is associated with certain types of cardiac disease. Therefore, the strong association of PSEN1 with early onset Alzheimer's makes it the correct answer.