Screening for Alzheimer's like Hemsworth "does more harm than good"

Experts are making a case for population-wide genetic testing but Alzheimer's is not a condition that would be considered for it.

Experts are making a case for population-wide genetic testing but Alzheimer's is not a condition that would be considered for it.

Genetic screening for Alzheimer's, which Chris Hemsworth underwent for a recent docuseries, could “do more harm than good” since the genetic risk information is not considered “medically actionable”, experts say.

Meanwhile, the growing popularity of home-testing DNA kits like 23andMe is burdening Australia's publicly-funded clinical genetic services.

Pioneering researcher in preventive DNA screening Paul Lacaze said their “general position is that people should not undergo genetic testing for APOEe4 and dementia risk, especially when young and healthy like Chris Hemsworth”.

Hemsworth, 39, took a slew of genetic tests in the US for the Disney+ documentary series Limitless about living longer and healthier. He later revealed he would "take time off" acting after he discovered he had two copies of the APOEe4 gene which was related to an increased risk of developing Alzheimer's disease.

Chris Hemsworth at the premiere of "Limitless With Chris Hemsworth". Picture: Dia Dipasupil/Getty Images

Associate Professor Lacaze heads DNA Screen, a Federal Government-funded pilot study of 10,000 18 to 40-year-olds. It aims to prove that DNA testing should be available to the public for free for a number of “medically-actionable” conditions including hereditary breast and ovarian cancer, Lynch syndrome (associated with a risk of bowel and endometrial cancer), and genetic high cholesterol. He said they now had evidence this population testing is cost-effective for the healthcare system and scalable. 

“Those three conditions, we think are so actionable, and if you carry the gene it puts you at such high risk that we think it’s in society's and the public health system's best interest to offer free genetic testing to anyone who would want it for those conditions."

That's not the case for Alzheimer's. 

While there are some “lifestyle modifications” you could make for dementia such as optimi

sed sleep, physical exercise, and social connectivity, “there are no real (medical) interventions or prevention available for dementia, to reduce your risk", Associate Professor Lacaze said.

"Therefore, the genetic risk information is not considered ‘medically actionable’ and may actually do more harm than good," he said.

Also, tests for APOEe4 are often not available in clinically-accredited settings and the quality of data from at-home tests is not assured. 

He added if Chris Hemsworth wanted to take out life insurance, he would likely need to provide his results to the insurance company which could decide whether or not to insure him based on his risk.

At present, Medicare funds testing for breast and ovarian cancer, Lynch syndrome, and genetic high cholesterol, but the criteria are "restrictive" meaning only a small number of people who would benefit from the tests can get them. 

The restrictive nature of current testing criteria through the Australian healthcare system was why a lot of people turned to online consumer testing, which he said was “problematic”.

RPA Hospital Cardiac Genetic Counsellor Jodie Ingles said she had distressed patients coming into the clinical setting who had “direct-to-consumer (DNA) testing go wrong”. 

“People getting reported back genetic findings that we know are the cause of Arrhythmogenic Cardiomyopathy that can cause sudden death … and freak out,” Associate Professor Ingles said.

“So those people end up in clinical services that are way overstretched in the first place.”

“But we don't really know the penetrance (of a gene) or anything like that. So we don't know if they'll actually ever develop anything," she said.