Alzheimer's disease: the hypotheses, known and unknown connections between UV-radiation, mtDNA haplotypes and life span - a review.

Alzheimer's disease (AD) is the most common neurodegenerative disease with controversial etiology. One theory claims that AD is due to brain aging affecting mainly the functions of mitochondria, therefore, the factors leading to mitochondrial ageing should lead to the development of Alzheimer's disease. Another theory is that different mitochondrial DNA haplogroups can be predisposition for the onset of the condition. Here we focused on the possible connection between AD and UV radiation using the data on the monthly UV index in Europe, its correlation with mortality rate due to AD and mitochondrial DNA haplogroups distribution. If a link between the two theories is proved, it will mean that UV radiation is a risk factor not only for skin cancer but also for a large group of neurodegenerative diseases amongst which is the Alzheimer's disease.