Gene Explains Why Women Are More Vulnerable to Alzheimer's

Researchers have determined that a single gene variant is responsible to giving aging women a much higher risk of developing Alzheimer's disease, compared to men of the same age.

A previous MD Connects article published back in March reported how the Alzheimer's Association 2014 Alzheimer's Disease Facts and Figures report focused on several key findings that indicated that women are far more likely to suffer from Alzheimer's disease than men in late-adulthood. Interestingly, the report also wrote that women in their 60s are nearly twice as likely to develop early symptoms of Alzheimer's than they are breast cancer, even when most medical attention is given to the latter when addressing the women's health.

Now a study that was published in the Annals of Neurology details new findings that not only indicate that the Alzheimer's Association report was correct, but also explain why women are in-fact more vulnerable to developing the disease than men.

According to a Stanford School of Medicine press release, the study's senior author Michael Greicius first became curious about the male vs. female risk rate of Alzheimer's back in 2012 after unearthing a paper published in a JAMA scientific journal back in 1997 that suggested that a ApoE -- a "genetic protein recipe " that is invaluable to the process of shipping fatty substances along nerve cell membranes -- could be expressed in more potentially damaging varieties among women. One variety in particular, called ApoE4 was commonly expressed in women and was found to be leading to an increased risk of developing Alzheimer's disease.

While the 1997 study was never followed up on for various reasons, Greicius decided to get a team together to investigate this phenomenon using modern techniques to asses gene expression.

Analyzing public data on more than 8,000 people around the age of 60 who had been admitted to Alzheimer's centers in the United States, the team determined that the risk of developing full-blown Alzheimer's disease was highest in individuals carrying the ApoE4 gene variant.

Interestingly, where the researchers then compare risk rates among women with the gene compared to men with the gene, they were able to determine that the gene only led to a slight increase in risk among males, while women who expressed the variant boasted nearly double the risk of developing Alzheimer's compared to women who did not express the gene in that manner.

Brain scans of the gene carriers showed a similar theme, where as men with the gene commonly showed brain scans no-different from their non-ApoE4 expressing counter-parts, while women with the gene variant showed remarkably different looking brain connection compared to non-carriers of the variant.

The authors of the study write that it is still unclear why the variant has such a more severe effect on the brains of women, but simply identifying the variant's influence is a huge step in the right direction.

The study was published in the Annals of Neurology on April 14.