Table 3. Early-Onset Familial Alzheimer Disease (EOFAD): Molecular Genetics.
| Locus Name | Proportion of EOFAD | Gene Symbol | Chromosomal Locus | Protein Name | Test Availability |
|---|---|---|---|---|---|
| AD3 | 20%-70% | PSEN1 | 14q24.3 | Presenilin-1 | Clinical |
| AD1 | 10%-15% | APP | 21q21 | Amyloid beta A4 protein | Clinical |
| AD4 | Rare | PSEN2 | 1q31-q42 | Presenilin-2 | Clinical |