Gobble

23 Chromosome Pairs; 4 Alzheimer's Genes Identified:

Amyloid precursor protein (APP),
discovered in 1987, is the first gene with mutations found to cause an inherited form of Alzheimer's.

Presenilin-1 (PS-1),
identified in 1992, is the second gene with mutations found to cause inherited Alzheimer's. Variations in this gene are the most common cause of inherited Alzheimer's.

Presenilin-2 (PS-2),
discovered 1993, is the third gene with mutations found to cause inherited Alzheimer's.

Apolipoprotein E-e4 (APOE4),
discovered in 1993, is the first gene variation found to increase risk of Alzheimer's and remains the risk gene with the greatest known impact. Having this mutation, however, does not mean that a person will develop the disease.