Clinical and Genetic Study of Neurodegenerative Disorders With Cognitive Impairment

Patients with different types of dementia will be recruited and evaluated in national hospital departments for their usual neurological follow-ups. A blood sample will be proposed in the field of this research project, and the biological material will be stored at the DNA and Cell Bank of Institut de Fédératif Recherche (IFR) of Neurosciences (Pitié-Salpêtrière Hospital, Paris). The clinical research network is already set up for Alzheimer's disease and frontotemporal dementias, which permits an evaluation according to a clinical standardized protocol.

Among these disorders, a monogenic sub-group has been identified. In Alzheimer's disease, it is associated with the APP, PSEN1 and PSEN2 genes, which account only for 75% of the familial forms with early onset. In frontotemporal dementias, the tau gene mutations account only for 10% of the cases with an autosomal dominant inheritance. The identification of familial forms with a genetic inquiry in the relatives is essential for a greater knowledge of the molecular bases of forms not caused by the known genes, using linkage approaches and candidate gene analysis. The familial forms are also useful for identifying the modifier genes.

In the multifactorial forms, the aim is to assemble a wide cohort of patients and controls matched for localizing and identifying susceptibility genetic factors. The strategies will use a candidate gene approach, and in the near future, studies of single nucleotide polymorphisms (SNPs) spread out in the whole genome. Meanwhile, similar approaches, particularly with candidate genes, could be used for identifying predictive factors of tolerance and response to the treatment.

Finally, correlations will be performed with seric markers according to each kind of dementia.

Specialized clinical teams in diagnosis and follow-up in dementias are assembled for this project, and in the study of neurological disorders of genetic origin.