Affiliations: Institute of Psychiatry, University of Bologna, Italy | Section of Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, University of Perugia, Italy
Correspondence:
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Corresponding author: Alessandro Serretti, MD, Institute of Psychiatry, University of Bologna, Viale Carlo Pepoli 5, 40123 Bologna, Italy. Tel.: +39 051 524100; Fax: +39 051 521030; E-mail: alessandro.serretti@unibo.it.
Abstract: Genetic factors have a variable impact on Alzheimer's Disease (AD), ranging from familial forms that are transmitted in an autosomal dominant fashion to sporadic AD, where a polygenic component is present. Most genes conferring susceptibility to AD are related to amyloid-β deposition (APP; PS1; PS2; APOE; Cystatin-C; ubiquilin-1), oxidative stress (NOS2; NOS3) and inflammatory response (IL-1 α; IL-1 β; IL-6; TNF-α). Genome-wide analyses, transcriptomics and proteomics approaches have pointed also to proapoptotic genes as increasing AD liability. Depression and psychotic symptoms that occur in a large proportion of AD patients have been associated with monoamine genes coding for metabolic enzymes (COMT), transporters (5-HTTLPR) and receptors (DRD1; DRD3). Genetic testing may be useful to confirm the diagnosis of AD in individuals with clinical signs of dementia, while it is generally not recommended as a predictive testing for AD in asymptomatic individuals. Drugs currently in use to treat AD are effective in only 20% of patients; their therapeutic effect is predominantly under genetic control (CYP26 gene; APOE). Environmental factors have been shown to moderate the effects of genes on psychiatric disorders such as depression, schizophrenia and ADHD. The study of gene-environment interactions in AD, that are still poorly understood, is essential to predict disease-risk in asymptomatic individuals. Genomics will provide a dynamic picture of biological processes in AD and new targets for the forthcoming anti-AD drugs.
