杏吧原创

Carrying a copy of the 鈥淎lzheimer鈥檚 gene鈥� doesn鈥檛 significantly raise a man鈥檚 risk of developing the disease.

The gene does increase a woman鈥檚 risk, but women with one copy of the gene were as likely to develop the disease as men with no copies. The study 鈥� along with work suggesting that the gene is associated with educational achievement in young people 鈥� highlights how much remains to be done to untangle the genetics of Alzheimer鈥檚.

In 1993, it was discovered that people with Alzheimer鈥檚 were more likely to carry a variant of the APOE gene called APOE4. Carrying one copy of APOE4 can .

Perhaps it鈥檚 more complicated than that, says at Stanford University in California. 鈥淭here is no question that APOE4 is a potent genetic risk factor for Alzheimer鈥檚,鈥� he says. 鈥淸But] it appears from our study to vary strongly as a function of sex.鈥�

Gender bias

We already know that there is a strong gender component to Alzheimer鈥檚: . In the 1990s, several papers flagged the possibility that .

To explore this further, Greicius and his colleagues looked at data from 5500 healthy people who had been tested for their APOE variant between 2005 and 2013. During this time, 960 were diagnosed with Alzheimer鈥檚 disease or a precursor to it.

Women with a single copy of APOE4 were 1.8 times more likely to fall into this group than women without the variant. For men, carrying a copy didn鈥檛 raise their risk.

鈥淢en with one copy of the APOE4 gene probably shouldn鈥檛 worry more than men without an APOE4 gene,鈥� says Greicius 鈥� although he says that anyone with two copies of the gene has a high chance of developing Alzheimer鈥檚.

Puzzling result

But it鈥檚 not all bad news for women. Although carrying one copy of the gene does increase their risk of developing the disease, women in the study were less likely than men to develop Alzheimer鈥檚 in the first place. This is a puzzling result given that to Alzheimer鈥檚.

鈥淭his was a surprising finding, and one we aren鈥檛 sure yet how to interpret,鈥� says Greicius. Working out what鈥檚 going on will be a target of future research.

at the Wadsworth Center in Albany, New York, was . She is a fan of the new study. 鈥淚t took 20 years but I am glad that it鈥檚 finally being recognised in a big way,鈥� she says. 鈥淗opefully this time it will register for good: sex should be in the equation when dealing with APOE.鈥�

Journal reference: Annals of Neurology, DOI: 10.1002/ana.24135