13 January 2009

The female dementia gene

Researchers from the American Mayo Clinic have discovered a gene, one of the variants of which significantly increases the risk of Alzheimer's disease. Since this gene is located on the X chromosome, women are at increased risk, Science Daily reports.

In search of new genetic factors predisposing to senile dementia, the researchers conducted a complete analysis of the genomes of 844 patients with Alzheimer's disease and 1,255 healthy volunteers who made up the control group. A comparison of the data obtained showed that people suffering from neurodegenerative disease have a gene called PCDH11X more often.

This gene is responsible for the synthesis of a protein involved in the regulation of the interaction of nerve cells. Since PCDH11X is located on the sex X chromosome, women can have two copies of it, and men can have only one.

To clarify the data obtained, the genomes of 1,255 more patients and 1,209 healthy Americans were examined. As a result of the final calculations, it turned out that the presence of one copy of this gene variant is associated with an increase in the risk of Alzheimer's disease by 18 percent in men and by 26 percent in women. In women with two copies of the gene, the risk of the disease was already increased by 75 percent.

According to the researchers, PCDH11X turned out to be the first gene whose effect on the risk of senile dementia is related to the gender of patients. The importance of the discovery also lies in the fact that despite the relatively small indicators of additional risk of disease, this variant of the gene is extremely widespread.

The most serious genetic risk factor for Alzheimer's disease known at the moment is the APOE 4 gene. The presence of two copies of this gene increases the likelihood of developing the disease by 11.5 times, one copy – by 4.8 times. The total number of genes somehow associated with Alzheimer's disease is approaching 400. However, according to scientists, in the vast majority of cases, heredity is not the main cause of the development of this type of senile dementia.

Copper news based on BBC materials: Women-only gene link to dementia 

Portal "Eternal youth" www.vechnayamolodost.ru13.01.2009 

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