Our ‘kind’ kids face devastating future due to rare ‘spelling mistake’ on their DNA – we’re in a race against time
WHEN Mel and Charlie Dixon were told two of their three children had a life-altering, ultra-rare genetic condition, there was still worse news to come.
Rosie, nine, and Tom, 14, were diagnosed with a mutation of the DHDDS gene, a condition which causes tremors, coordination issues, seizures and learning difficulties.
The children are two of around only 70 people worldwide to have been diagnosed with the condition, according to the geneticist involved in making their diagnosis.
Much to the parents’ horror, they soon discovered there was no treatment and little research into the DHDDS gene, which was a “difficult pill to swallow”.
To make matters even worse, the condition can lead to Parkinsonism and dementia, which made the couple feel like they were in a “a race against time” to find treatments.
“We’re basically waiting for symptoms to progress, and then we’re just reacting to their symptoms,” the mum said.
Mel and her husband Charlie, who works in fund management, have three children – Tom, 14, Harry, 12, and Rosie, nine.
Tom and Rosie were “late with all the milestones”, such as walking and speaking, the mum said.
Both were diagnosed with mild learning difficulties and dyspraxia, which affects their co-ordination, while at primary school.
At the age of seven, Tom was diagnosed with autism as well – but before this, Mel and Charlie had started to notice a “tremor”, which was “the anomaly”.
“When he was going to do certain movements, I would notice his hand shake, and it just seemed to be increasing,” Mel said.
There’s nothing greater than fighting for your children
Mel Dixon
The family met multiple neurologists, but no cause for the tremors or learning difficulties was discovered, so they decided to go to a private clinic which screened for a range of genetic conditions.
The first panel of test results came back negative, so the couple hoped the children’s symptoms would improve over time – but this was not the case.
It was only after Tom and Rosie underwent whole genome sequencing testing at St George’s Hospital in London, which can detect changes in your genetic makeup, that the DHDDS gene mutation was discovered.
“We got the call from the geneticist, and she said they’ve both got identical variants,” Mel said.
“They’ve got one spelling mistake (a mutation) in a very important part of their DNA.
“We’ve all got spelling mistakes, but it’s where they are, and their mistake is in the wrong place.”
Mel described the diagnosis as “overwhelming” and “devastating”.
At the time, the only source of information was a medical paper, which contained details of 25 case studies with the DHDDS gene mutation.
She and her husband have since found that biotin – a vitamin – has helped to reduce the children’s tremors, meaning drinking from a cup is now “more manageable” for them, but they are not stopping there.
Day to day, the two children use weighted cutlery to eat because their hands are not “steady enough”.
They use heavy glasses, which are half-full, to prevent spillages, and pencils to help with their grip.
In addition, they struggle with balance and learn at a slower pace than most children their age.
Symptoms of DHDDS gene
THE DHDDS gene mutation can cause neurodevelopmental and sometimes neurodegenerative issues.
It affects people to varying degrees, meaning some people experience more severe symptoms than others – although scientists don’t understand why this is.
There is currently little known about the condition, which has so far only been diagnosed in 70 people worldwide.
Symptoms include:
- Learning difficulties
- Tremor
- Seizures
- Co-ordination issues
Less common symptoms are:
- parkinsonism
- Dystonia
- Dysarthria
- Autistic traits,
- Hyperactivity
- Anxiety
- Psychosis,
- OCD
Source: Cure DHDDS
Mel said: “Even if you meet Tom and Rosie briefly, you may not notice they have challenges – yet every day this mutation is untreated, it’s causing them damage.
“They’re kind, resilient, funny, and loving.
“My daughter loves singing and dancing, and my son loves technology, cars, and trains.
“He [Tom] always looks out for Rosie and makes sure she’s okay, and Harry is very protective of them both.”
Charity launch
Given there is currently no treatment, Mel and Charlie are fearful of the future as they do not know how quickly their symptoms could progress.
This is what led the couple to set up their charity, Cure DHDDS, in 2023, which aims to both support families affected with these rare mutations and drive research and fund potential treatments.
“Our hope is that if we can help some of those symptoms, or stop them from getting worse, they could potentially be independent later on if we can intervene in a timely manner,” the mum explained.
“They both have so much joy to give the world, and are more than worth every bit of this fight,” she added.
The costs of this work, however, are high, and the family has to fund it themselves, which is why they have set up a GoFundMe page, which has so far collected over £48,000.
They have 11 ongoing research projects, and they held the first DHDDS conference online last year, which was a “proud moment.”
“It feels like a race against time,” Mel said.
“But the way I function and the way I’ve dealt with this is just never give up, and I really feel that if I give this my all, I can make a difference.
“When you’re told there’s nothing they can do, don’t accept it.
“Work and fight for what you believe, and there’s nothing greater than fighting for your children.”