Ekaterina Rogaeva, PhD, Associate Professor, Centre for Research in Neurodegenerative Diseases, University of Toronto, Department of Medicine, Toronto, ON.

There are at least four well-confirmed genes responsible for Alzheimer’s disease (AD), the most common form of dementia. In addition, many reports indicate an association between the disease and genetic variations in different gene candidates. The complexity and interpretation of these studies are discussed using, as an example, the recent discovery of the association between AD and the SORL1 gene. The knowledge obtained from AD genetics is applicable to many other forms of dementia, which are also genetically complex disorders and are almost all associated with the deposition of different aberrant proteins in the brain.
Key words: Alzheimer’s disease, gene, APP, APOE, SORL1.

Yosuke Wakutani, MD, Centre for Research in Neurodegenerative Diseases, Departments of Medicine, University of Toronto, and Toronto Western Hospital Research Institute, Toronto, ON.
Peter St. George-Hyslop, MD, Centre for Research in Neurodegenerative Diseases, Departments of Medicine, University of Toronto, and Toronto Western Hospital Research Institute, Toronto, ON.
Ekaterina Rogaeva, PhD, Centre for Research in Neurodegenerative Diseases, Departments of Medicine, University of Toronto, and Toronto Western Hospital Research Institute, Toronto, ON.

There are ~200 human diagnostic categories presenting as or accompanying dementia (interested readers may investigate the database Online Mendelian Inheritance in Man, a catalog of human genes and genetic disorders, at www.ncbi.nlm.nih.gov/ genome/guide/human/). Many forms of dementia are associated with deposition of different aberrant proteins in the brain. Familial aggregation in Alzheimer’s disease (AD), frontotemporal dementia (FTD), and other forms of dementia implies the presence of inherited susceptibility factors. Many forms of dementia remain genetically unexplained; however, linkage analyses suggest that most of them are complex disorders with several underlying genetic factors. Here we provide an update on known genes responsible for dementia with the strongest focus on AD and FTD, which are the most common forms of dementia.
Key words: dementia, Alzheimer’s disease, gene, APP, APOE, frontotemporal dementia.