Credit, Katie Doy
If you could find out if you have a gene that could reduce your life expectancy, would you get tested?
That was the dilemma faced by Laura Sides when she was given the opportunity to have a genetic test for a rare form of early-onset dementia, diagnosed in her father when he was in his early 40s.
Sides told Sian Williams, host of BBC Radio 4's Life Changing podcast, why he decided to take the exam and how this choice changed his life.
Sides says that she was always very close to her father, with whom she had a "similar way". He was a family doctor and "a very loving and dedicated father", according to her. When his Alzheimer's symptoms worsened, Sides dropped out of university to care for him.
"We had a really good time together," recalls Sides, recalling trips to a lighthouse and his habit of collecting cup holders. "I would run baths for him, play music and pour jugs of hot water over his head. He loved it."
Credit, Laura Sides
It was during a doctor's appointment with his father that Sides learned he had a 50 percent chance of developing the same form of early-onset Alzheimer's, known as the "London variant."
“All I could think was that it was like making a coin toss,” says Sides. "I was still very involved with everything that was going on with him [his father]. So I just tried to put it aside, without thinking about it."
Sides' father died in 2009, just a year after his mother's death.
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“Suddenly, I felt a huge desire to leave,” he says. She then decided to travel the world alone and ended up settling in Melbourne, Australia.
It was there that the possibility of having inherited her father's illness began to worry her. In 2013, Sides saw a specialist.
The doctor explained that a genetic test could determine, with 99.999% certainty, whether she had inherited the genetic condition associated with early-onset dementia. If he had the gene, the first signs of deterioration would be expected between the ages of 46 and 48, according to him.
"I thought: I'm not ready for this yet. I don't want to take the test."
As he entered his 30s, Sides began thinking more and more about genetic testing and decided he wanted to know the results. But first he needed to undergo six months of genetic counseling.
"There are few situations in life where we can find out what the future holds for us, and dealing with this information can be very difficult," he says.
After six weeks of waiting, the day finally arrived to receive the test results. Sides says she was "extremely nervous."
She had arranged to have lunch with a friend after the appointment, but decided to go in alone to receive the results.
"I said, 'Let's get straight to the point.' They responded, 'We're sorry, but we don't have good news. You inherited the gene.'"
Sides remembers sitting there, "with the feeling that everything around her had turned into an indistinct noise."
"When I left the room, my friend started crying desperately." Sides, however, did not react. "We went to lunch and it was very pleasant. I don't know if I already understood what that meant."
Reality only hit her later. "I was angry. I thought it was all very unfair. I was completely lost, not knowing how I should live from now on. How can I move forward knowing something like that?"
Sides began to feel the urge to return to the UK, especially as his sister was pregnant. "It doesn't make sense...living on the other side of the world when she's about to have a baby."
Still, Sides continued traveling the world while participating in clinical studies, both before and after receiving his diagnosis.
"It was very positive to be able to participate in something like this in the midst of such a difficult situation."
Sides is now 43 years old, three years younger than the age at which doctors predicted she would begin showing symptoms.
"I keep waiting for the moment when all this will come true. I imagine that one day my abilities will start to diminish, but I don't lose sleep thinking about it."
She says she is "grateful and very lucky for the people who are part of her life." But meeting someone and starting a new relationship is difficult.
"Should I tell? Is it better not to tell? When should I talk about this?"
"And most of the time I told it, the relationship was over."
However, Sides claims that some experiments showed "she was wrong".
"I discovered that I can be loved despite all of this. It's something that brings me a lot of security and joy."
Sides says she always imagined, "naively", that she would be a mother.
"[It was] one of the few things I never had any doubts about. I knew I would be a good mother and I really wanted to have kids. It's hard... but it doesn't make sense. It wouldn't be fair."
For Sides, life right now is about enjoying the things that make her happy.
"It's not about making big dreams come true. It's not like I want to see the Grand Canyon... I want to spend time with people I love and who make me feel safe."
"I love nature. I love being outdoors. I'm passionate about being in the water. It may sound cliché, but... I really believe that the little things are actually the most important."
"I hope to have a few more wonderful years in this world... drinking champagne and eating oysters, two of my favorite things."
Dementia and Alzheimer's disease
Dementia is not a single disease, but rather a group of symptoms caused by damage to the brain, of which memory loss and worsening of cognitive abilities are the most characteristic. Because it is more common, Alzheimer's disease is the best-known form of dementia. Vascular dementia then appears.
The two conditions tend to evolve differently.
“Alzheimer’s tends to be a disease that progresses slowly, like a path that descends a hill in a more or less homogeneous way,” explained Juan Fortea Ormaechea, neuroscientist at the Memory Unit at the Santa Cruz y San Pablo Hospital in Barcelona, Spain.
"On the other hand, vascular events can happen today - if you have a heart attack, you have brain damage, you recover in a few months, but there are consequences - and, if you don't have another heart attack and there is no other cause, you are stabilized. Or you could have another heart attack the following year and get worse again."
In other words, cognitive deterioration can occur in a staggered and more marked manner, as opposed to a more linear evolution.
According to Nikki-Anne Wilson, from Neuroscience Research Australia (NeuRA), at the University of New South Wales in Sydney, Australia, we still don't know exactly what causes Alzheimer's, but "we know that the disease is associated with the accumulation of two types of proteins called beta-amyloid and tau in the brain."
"Although we all have some beta-amyloid, when it accumulates in excess in the brain, it clumps together, forming plaques in the spaces between cells. These plaques cause damage (inflammation) to surrounding brain cells and lead to dysregulation of tau. Tau is part of the structure of brain cells, but in Alzheimer's these proteins become 'tangled'. This is toxic to the cells, causing them to die," Wilson wrote in an article published by BBC News Brasil.
Still according to Wilson, "it is believed that a feedback cycle then occurs, triggering the production of more beta-amyloid and more abnormal tau, perpetuating damage to brain cells."
Early-onset Alzheimer's disease
"Early-onset Alzheimer's disease causes chemical changes similar to those of the late form, but can affect different areas of the brain," explained Mark Dallas, associate professor of Cellular Neuroscience at the University of Reading, in the United Kingdom, in an article published by BBC News Brasil. He adds that damage to the hippocampus is also less in the early form.
But "the risk factors are similar in both forms of the disease," Dallas added. "Low levels of cardiovascular fitness and lower cognitive capacity in early adulthood, for example, were associated with an eight times greater risk of developing early Alzheimer's. However, all the factors that influence a person's chances of developing the disease are not yet known."
According to Dallas, "experts agree that genetics plays a role in about one in ten cases of early-onset Alzheimer's disease. So far, three genes (APP, PSEN1 and PSEN2) have been associated with the disease."
"These genes are all related to a toxic protein believed to contribute to Alzheimer's disease (known as beta-amyloid). When these genes become defective, there is an accumulation of beta-amyloid, which is linked to the onset of symptoms."
According to Dallas, more and more studies point to a possible relationship between traumatic brain injuries and the early development of Alzheimer's disease.
*This report was adapted from the BBC Radio 4 program Life Changing, presented by Sian Williams. You can listen to it in English here.
*Additional reporting by BBC News Mundo
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