The model’s ten-year-old son, Harvey, has Prader-Willi syndrome, which means he eats to excess and is prone to obesity and diabetes.
He also has septo-optic dysplasia, which causes blindness and growth hormone deficiency, as well as ADHD and autism.
This is why Katie, 34, is supporting Jeans For Genes Day tomorrow.
“I’m a parent of a child with disabilities so I know how important Jeans For Genes is,” Katie says.
“Harvey has got a genetic disorder. He has Prader-Willi syndrome, which means he has quite a big problem with food. He wants to eat all the time. Basically, his whole life revolves around food.
“We have to lock the freezer all the time now. He got up in the middle of the night and got out some frozen pizzas.
“He gets into the cupboard and hides. He thinks we can’t see him eating sweets.”
Katie says her son is also prone to aggressive outbursts.
“The bottom line is, you get a bit angry if you’re hungry,” she says.
“But Harvey is like that all the time. He has tantrums.
“He’s my son and I love him, but anyone who knows him knows he is the king of the house.
“He can be quite controlling. I have to close the car door in a certain way. If someone comes to the front door, they have to ring the bell, or he goes mad.
“Any kids who come to my house tend to be a bit wary of Harvey.
“He might be sitting here one minute, then he’d turn around and whack one of them. He finds it funny.
“It can be quite challenging but I wouldn’t change him for anything.
“People might wonder why I let him do it. But I’m not letting him. That’s just the way he is.”
One in 25 children in the UK suffers from a genetic disorder and since it became a national appeal in 1996, Jeans For Genes has raised more than £12million to help them.
“What this charity does is vital,” says Katie.
“People say, ‘It’s OK for you, you’ve got money’, but my money doesn’t make a difference.
“It won’t change Harvey’s condition. He will still be disabled.
“What we need is to find out more about genetics.
“Whether it’s for a scientific report, or advice and support when caring for a child, the money the charity raises is incredibly important.
“And all you have to do to help is wear your jeans for a day. I’ll be wearing mine.”
Prader-Willi affects no more than one in 15,000 English-born children. There is no cure.
Basically, a baby fails to receive a complete set of chromosomes. There are many ways this can happen and it is rarely hereditary.
There are more than 6,000 genetic disorders. Though individually rare, collectively they are the biggest killer of young children.
These parents have all been told their children have life-limiting conditions, so how do they cope?
What do they tell their children? And how far ahead do they dare to think? Here, they share their stories.
‘Kyran wants to play professional football. He doesn’t know how ill he is’
KYRAN RICHMOND, nine, from Durham, lives with brothers Cameron, 13, and Hayden, six, mum Debbie, 32, and dad Carl, 38.
Last year he was diagnosed with Juvenile Batten disease. Debbie says:
Kyran was just like every other lad until he failed an eye test when he was six. He got glasses, but I knew something was wrong when he started bumping into things.
We went back to the hospital and they diagnosed him with Juvenile Batten disease.
The first thing I said was, ‘Is there a cure or any treatment?’ And when she said ‘no’ I burst into tears.
Then I asked the life expectancy and she said late teens to early twenties.
There are only 200 children in the UK with the condition and the prognosis varies but generally children start to lose their sight, get seizures, lose motor skills, speech and mental capacity.
The end game is 24-hour care in bed until they pass away.
Kyran had his first fit when we were on holiday this year and has had two more since.
I know eventually he’ll start losing the use of his limbs and will be in a wheelchair. He’ll not be able to chew or swallow but they can’t tell us when any of that is going to happen.
Kyran doesn’t know how ill he is, so he always talks about the future. He wants to be a footballer and play for Newcastle United.
But sometimes he says he wishes the hospital would let him die or kill himself. I tell him, ‘The hospitals are trying to help you’.
Jeans For Genes helped fund a Batten disease weekend we went to this year.
There was a family from New Zealand with their son, Brad, who has the same condition and was 21.
The idea Kyran could get to his twenties or thirties if we keep him motivated is amazing.
‘Scarlett is the happiest girl ever’
SCARLETT HOPE, three, from Kent, lives with sister Tia, six, mum Susie and dad Robert, both 36. Her Cockayne Syndrome was diagnosed in 2010. Robert says:
Scarlett was only 4lb 6oz at birth and failed the hearing test.
The doctors told us not to worry, but came out and did a hearing test at home at five weeks – and she failed that.
We went to hospital for a more detailed test. She failed that, too, and we were told she was deaf.
By three months old, she didn’t seem to be putting on weight, and when she was looking at you she wasn’t focusing. It was like she was looking past or through you.
She was tested and monitored for months and, when she was just past one, they did an MRI scan.
It showed her entire inner ear was effectively missing – she had no balance system, auditory nerves or cochleas and wouldn’t be able to have implants to help her hear. She would be unable to speak.
She’d also had a skin biopsy and the same month we got the MRI results, we were told she had Cockayne Syndrome.
The average lifespan of a child with this is 12. It’s a genetic premature ageing condition with developmental delays and degeneration of the nervous system.
Devastated, we shut ourselves away for months. But in December 2001 we emailed the charity Amy And Friends. It’s part-funded by Jeans For Genes.
Although I emailed on Christmas Eve, the lady who runs it called me at 10.30pm for a chat. They helped us afford a retreat for children with CS, where we met the boss of Scarlett’s geneticist.
She told the doctor to see Scarlett and they said she’d improved too much mentally and physically to have CS. It was a year ago and they’re still looking for what she’s got.
If Jeans For Genes hadn’t helped, Scarlett would have the wrong diagnosis.
‘Rubi proves kids with genetic disorders can thrive’
RUBI SAUNDERSON, seven, from Sheffield, lives with her brothers Liam, 16, and Luke, nine, mum Julie, 39, and dad Darryl, 46.
She was diagnosed with Trisomy 18 as a baby. Julie says:
Rubi stopped breathing just after she was born.
I screamed for the nurse and they resuscitated her. It was terrifying.
When she was nine weeks old, the doctors did an ultrasound and found she was missing a big part of her diaphragm. All her organs were crushing her heart and her lungs. The condition is called congenital diaphragmatic hernia.
They operated that night. She came through surgery and we took her home on Christmas Eve.
When she was 16 months old, she was still struggling to gain weight and we were told she had Trisomy 18 mosaic.
It means she has three chromosome 18s instead of two like the rest of us.
Children with the condition have mental and physical development problems. There are only five other children in the UK with the condition.
They told us she would never walk, talk or sit up and that it was a miracle she was alive. I think I went into shock. I was devastated. It seemed so unfair.
I want Rubi to have a happy, full life and be given a chance to be like everyone else.
She’s at a normal school with one-on-one care and she loves it. Being with other children has brought her on more.
Her speech has come on and now she says odd words.
She loves playing with her brothers too.
She’s walking now. Not like a seven-year-old – she wobbles and falls – but to see her doing so well after what we were told is brilliant. She loves dancing too.
Jeans For Genes is so important. I want people to realise that with a bit of support and encouragement, children with genetic conditions can thrive just like everyone else.
How you can help
GO to jeansforgenesday.org to find out how workplaces and schools can take part.
To donate by post make cheques payable to Jeans For Genes, with your address on the back and post to Jeans For Genes Day, Freepost ANG2739, Colchester, CO2 8BR.
Donate by phone on 0800 980 4800, or via JustTextGiving, text any amount and the code JFGD12, to 70070. For example, to donate £10 text JFGD12 £10 to 70070.