Introduction: Alzheimer's disease (AD) is the first cause of dementia (60-80%). The causal genes with autosomal dominant inheritance in the early onset forms (APP, PSEN-1, PSEN-2) and one susceptibility gene in the late onset forms (APOE) are described.
Development: Causal genes involved in the early onset forms account for approximately 5% of the total. Among all the susceptibility genes, only the APOE gene, involved in the late onset forms, has been replicated in all the studies. However, it has not been possible to replicate the more than 200 genes in family or case-control studies. Nonetheless, the genetics of Alzheimer's disease is very complex. The models that have the most influence in its most frequent phenotypes are multifactorial ones (genetics and environmental ones).
Conclusions: AD is a disease with a complex inheritance. The early onset forms have supposed a great advance in the knowledge of the ethiopathogeny of the disease. However, especially valuable information could be extrapolated from knowledge on the late onset forms given its similarities with the most prevalence forms, that is, the sporadic ones.