**Acknowledgements**

Caucasian subjects, showed that the reduced apoE plasma level may be a predictor of a transition from MCI to AD. Moreover, the plasma apoE concentration correlates positively with cognitive function, and patients with a lower apoE level tend to perform worse in

Hence, the assessment of the plasma apoE concentration and the *APOE* status may give valuable information to physicians trying to predict the rate of cognitive decline in the course

The appearance of dementia in old age is influenced by both biochemical and genetic factors leading to structural disorders in the brain of elderly persons. The level of Aβ is mentioned among the other biochemical factors associated with dementia. The deposition of Aβ in the brain is controlled by *APOE* and by genes associated with the amyloid cascade (*APP, PSEN1*, and *PSEN2*). Subsequently, Aβ toxicity is modified by the *TOMM40*. In the elderly, also abnormal cholesterol, glucose levels, and the weakening of protective and repair mechanisms leading to the generation of ROS (mediated, e.g. by *PON1*) may cause a reduction in cognitive functions. However, the role of genes associated with longevity (e.g. *FOXO3A, CETP*) and normal aging (e.g. *SIRT1, AKT1, CDKN1A*) is not clearly defined in the occurrence of diseases

Finding a way to control the genetic factors and their protein products may contribute to the prevention of diseases of old age, including depression and dementia, and to improve the

**Figure 3.** The genetic and biochemical factors associated with normal aging and dementia; β-amyloid—Aβ.

neuropsychological tests assessing spatial memory and language abilities [89].

of dementive disease as well as in normally ageing adults and elderly persons.

**7. Summary**

264 Update on Dementia

typical for this age group, as shown in **Figure 3**.

quality of life of elderly people.

This study was supported by the Poznan University of Medical Sciences grant no. 502-14-01111677-10342.
