EN
			
			
			A significant component of the aging process is genetically           determined. Numerous theories of aging exist, many of which postulate the       existence of "longevity genes". Recent advances in molecular biological and     other techinques have allowed a significantly greater understanding of aging and age-related disease. This will be illustrated by four genetic and sporadic     diseases: Alzheimer's disease (AD) and related disorders, transthyretin         dementia, cerebral amyloid angiopathy-Icelandic type and scrapie related        diseases. Alzheimer's disease (AD), the most common of this group, is the       leading cause of dementia in Western countries. Recent genetic and biochemical  studies have shown in involvement of at least four genes in the pathogenesis of AD. In early-onset familial AD mutations in the (beta)PP, S182 (presenilin 1)   and STM2 (presenilin 2 or E5-1) genes have been found, while in the more common late-onset AD the presence of the apolipoprotein E4 isotype is a major risk     factor. Genetic studies have also helped to elucidate the etiology of rarer     cerebral amyloidoses such as the recently described Hungarian amyloidosis that  is characterized by meningocerebrovascular amyloid deposition, with resultant   dementia. This disease is linked to a mutation in the transthyretin gene. It is hoped that in the near future this increase in knowledge will allow the         development of therapeutic approaches to slow the aging process.