Table 1.

Genetic factors predisposing to AD: relationships to the β-amyloid phenotype

Chromosome	Gene defect	Phenotype
21	βAPP mutations	Increased productions of all Aβ peptides or Aβ42 peptides
19	ApoE4 polymorphism	Increased density of Aβ40 plaques and vascular deposits
14	Presenilin 1 mutations	Increased production of Aβ42 peptides
1	Presenilin 2 mutations	Increased production of Aβ42 peptides