Australian sisters with guaranteed Alzheimer’s gene face new drugs, blood test and prevention hopes

Megan and Jillian, identical twins and practising nurses from a small town in Victoria, were told in June 2022 that they each carry a pathogenic PSEN1 mutation, a genetic change that guarantees they will develop early-onset Alzheimer’s disease. Their mother and several other relatives had previously died from the same condition, making the diagnosis a profound personal blow. Since then, Australia has approved two breakthrough amyloid-targeting medicines and introduced the PTau217 blood test, which can identify Alzheimer’s-related changes up to 20 years before clinical signs appear.

The World Health Organisation’s latest dementia guidelines now emphasize that nearly half of all cases are linked to lifestyle risks such as tobacco use, poor diet, physical inactivity, high blood pressure and diabetes. Researchers highlight the importance of exercise, cognitive-reserve activities and even routine vaccinations in lowering risk. The twins have joined a trial that combines lecanemab with an experimental tau-targeting agent, while they adopt healthier habits and advocate for legal reforms around assisted dying for dementia patients. Their story illustrates how genetic certainty is meeting emerging therapeutic and preventive options that could reshape the outlook for many at risk.