Penny, 4, robbed of her ability to walk and talk overnight by cruel genetic disease
Little Penny Stewart had just started to walk when Rett syndrome took over
WHEN little Penny Stewart was two years old, she was like any other toddler.
She could walk, was learning to talk and was hitting all her milestones.
But, the toddler's development was to come to a sudden and drastic halt, due to a cruel genetic disease.
Almost overnight, the toddler started to lose the ability to talk and use her hands - and within a year, she could no longer walk unaided.
Penny, now four, has Rett Syndrome - a rare genetic mutation that affects just one in 1,500 kids every year.
"It's horrible to watch," said dad Ben, 40.
"What Rett does is trick you into thinking you have a perfectly healthy child, and then it begins to happen.
"One of the big changes you have to make, as a parent, is altering your expectations: with other diseases you get treatment and you look for improvement, even if it's gradual, but as Rett parents, we are constantly bombarding our children with therapies just to stop things getting worse.
"It's just so cruel in the manner that it works: often you could reach three, your child could have 40 or 50 words, be starting to string sentences together, they can walk, and then they lose that.
"One day you have this happy little toddler and very shortly you will see them lose pretty much everything, apart from their personality."
Symptoms of Retts syndrome
According to the , it affects about one in 12,000 girls born each year.
There's no fixed age when symptoms appear in children - it varies from person to person.
And a kid with Retts may not have every symptom.
There are four stages to the condition.
1. Early signs: a child's development slows or stops, resulting in delay with speech development, mobility issues, difficulty feeding, low muscle tone and repetitive hand movements
2. Regression: when the child starts to lose some of their physical and emotional abilities, including eating, using hands, sleeping, or socalising
3. Plateau: many girls stay at this stage for most of their lives. They may show improvements in their behaviour but might start having seizures, irregular breathing patterns, teeth grinding and heart rhythm issues
4. Deterioration: can last for years or decades, and results in a curved spine, muscle weakness, losing the ability to walk
Rett syndrome is a rare neurological disorder which is usually caused by a faulty gene found on the X chromosome.
As such, the vast majority of cases are found in girls as boys rarely survive if they've only got one functioning X chromosome.
It causes people to have profound physical and communication disabilities.
It's Penny's bubbly personality that keeps dad Ben going, alongside the support of his eldest daughters Paige and Poppy.
He balances caring for his youngest with tirelessly fundraising for research into her condition.
The charity claims that there's a realistic possibility of effective treatments and maybe even a cure within the lifetime of kids like Penny.
That hope is what has driven Ben to undertake a series of increasingly difficult challenges, which include running 500 miles over the course of a year, taking part in 10K races wearing his purple "Rettman" superhero costume, having his legs waxed and taking part in Boxing Day cold water dips.
He's already raised over £1,000, and has pledged to complete more challenges for every further £500 raised.
He said: "I certainly believe that a cure is possible within her lifetime.
"My opinion is within the next few years we will see more pharmaceuticals, and then gene therapies, which are being worked on at the moment, will take more like 10 or 15 years to start to become available.
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"If I didn't believe research offered a realistic hope I wouldn't be doing this, but I believe this is the best course of action for children like Penny.
"That's what spurs me on to do all of this."
You can donate to Ben's JustGiving page and you can follow Ben's progress on Twitter,
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