Gene variant doubles dementia risk in men, no impact on women

Aussie researchers have identified a specific gene variant, found in one-third of people, that doubles dementia risk in men while leaving women unaffected.

Australian researchers have discovered a gene variant linked to dementia that doubles mens risk of the disease, but has no impact on women.

The team found Melbourne men in their mid-seventies who had two copies of a variant — known as H63D — had about a one in ten chance of developing dementia.

But men with one copy — or none at all — of H63D only had a 4.5 per cent risk.

Curtin Medical School co-author Professor John Olynyk said the variant was common — carried by one in three people — but only one in 36 people had two copies.

“Having just one copy of this gene variant does not impact someone’s health or increase their risk of dementia,” he said.

“However, having two copies of the variant more than doubled the risk of dementia in men, but not women.”

He said the variant impacted the haemochromatosis gene, which played a critical role in regulating the body’s iron levels, but they had not found a direct link between the blood’s iron levels and dementia.

The gene variant doubles mens risk of the disease, but has no impact on women. Picture: Supplied

“This points to other mechanisms at play, possibly involving the increased risk of brain injury from inflammation and cell damage in the body,” he said.

He said, while they could not change the genetic variant itself, they could potentially treat the “brain pathways which it affects” once they learn more.

“More than 400,000 Australians are currently living with dementia, with around a third of those being men.

“Understanding why men with the double H63D variant are at higher risk could pave the way for more personalised approaches to prevention and treatment.”

The study, published in Neurology, used data from a famous Australian-American trial — known as ASPREE — which was testing the health impacts of daily-low aspirin older people and collected a “treasure trove of healthy ageing data that has underpinned” numerous studies since.