Alzheimer’s: I know I’m going to have early onset dementia

James Bexon was just 33 years old when he was told he had between 20 and 30 years before developing Alzheimer’s disease.

His father was diagnosed aged 58, and in 2018 James took an NHS test which revealed he had a 99.9% chance of contracting a rare genetic form of the disease.

He qualified for an exam because of the strong family bond that made him wonder if he could pass it on to his own sons, Elijah and Jacob.

Neither son inherited the gene responsible for the genetic disease Alzheimer’s.

James was living in Tan-lan, Gwynedd, when he began the process of being tested for early-onset genetic Alzheimer’s disease.

His father died of the disease in late 2017, shortly before James’ tests began.

Half of his family members developed the disease over the years.

James had numerous counseling sessions before the blood test in March 2018, to prepare for the possibility of bad news.

The results came six weeks later.

“The counselor was accompanied by an intern and I saw it on her face when I walked in,” he said.

“We half-expect it anyway, because it’s big in the family. Obviously, if it was a ‘you don’t have it,’ that would be amazing.

“I just thought that was the hand I was dealt, I had that feeling, even though it was 50/50.”

He added: “The buildup of amyloid protein, which causes genetic dementia, shuts down your memory and slows everything down. It starts about 20 or 15 years before you experience symptoms.

“So actually it might have already started – I just don’t know.

“Sometimes you can dwell on it too much. Elijah is five and Jacob is two. As they get older, time flies.

“Suddenly you’re 40, and actually, I’m not far from 50.

“There are people who have parents in their 50s and 60s, and I want to have that. I want my children to have a real grandfather. The children have Gemma’s stepfather, but on my side, they don’t have a grandfather.

“It would be nice to live to be 70 or 80, to be a grumpy old man.”

James and his wife Gemma also had a difficult decision to make whether or not to test their two children for the gene while they were in the womb.

They decided to proceed with testing and both children tested negative.

You can only be tested on the NHS in Wales and England for rare forms of hereditary dementia, such as frontotemporal dementia and some forms of young-onset Alzheimer’s disease.

Jules Knight, nurse at Dementia UK, said: “Dementia UK statistics indicate that 7-12% of early onset cases are a genetic form of dementia.

“In the UK, 70,800 people are currently living with early-onset dementia.”

Drugs such as donanemab, which trials have shown to slow cognitive decline, rely on early diagnosis and private testing for other forms of dementia is not available on the NHS.

Ms Knight said there are some concerns about private tests, which only tell you risk, rather than NHS tests, which can identify a genetic mutation.

“The NHS test is definitive: you either have the genetic mutation or you don’t,” she said.

“The genetic risk variant, some of us might have the genetic variant that others might not have, but that doesn’t mean you will or won’t develop it.”

She also said the NHS offered significant emotional support.

“When someone is referred for genetic testing, they should have counseling before and after,” Ms Knight said.

“The prerequisite is assistance with whether you want to pursue testing, the implications of that, and what support you may need.”

For James, who now lives in Evesham, Worcestershire, the NHS test has reassured his family.

“We won’t have any more children, so we know it’s over for genetic Alzheimer’s.

“For me, it was all about trying to stop this in our family. There’s only so much we can do, and we did what we could.”