A disease so rare if I don’t wake daughter every 4 hours she could die

The family of a teen with a one-in-a-million condition live on a daily knife-edge – as she could die unless she swallows cornflour and water every four hours. Catherine McMillan was two-and-a-half years old when diagnosed with Glycogen Storage Disease type 1b (GSD1b), an ultra-rare genetic disorder that can lead to severe low blood sugar, an enlarged liver, and immune system defects.

Now aged 14, Catherine must drink a ‘formula’ of gravy ingredients, raw cornflour and water every four hours to help release glucose slowly and maintain blood sugar levels between meals. It enables the youngster, once of Westgate-on-Sea, Kent, but now living in Zamora, Spain, to attend school, yet her life will forever revolve around a regime of carefully-managed doses and mealtimes.

So parents Jason, 52, and Maria, 49, have told the Express they want to raise awareness of GSD1b while urging medics and drug giants to keep researching the devastating condition.

Devoted father-of-three Jason McMillan, 52, told us: “We have lost children in this community because a parent has overslept or a machine has broken. It’s horrifically sad.

“Catherine is a 14-year-old who looks at first glance just like any other teenager, but looks can be misleading. An enormous amount of work goes into keeping her well.

“The four-hour clock has not disappeared. The fact that treatment works should not make the disease invisible.

“Health systems do not need every doctor to recognise every rare disease – but they do need to recognise when the ordinary explanation no longer fits.”

GSD1b also affects the immune system, and Catherine has suffered from neutropenia – a blood disorder characterised by an abnormally low level of neutrophils (white blood cells that fight off bacterial and fungal infections), leaving her at risk of severe infections and inflammatory bowel disease.

In addition to the cornflour, Catherine takes empagliflozin, a repurposed diabetes drug that doctors found helps treat neutropenia.

Defiant Catherine explained: “Having GSD1b means I always have to think about food, cornflour, time and my health, even at school and during the night.

“Sometimes I just wish I could do the simple things my friends do without having to plan everything first. It can make me feel different, but GSD1b does not define me.

“A cure would mean freedom to sleep through the night, eat, go out with my friends and live without constantly having to think about what my body needs next.”

GSD1b is a genetic, metabolic liver disease that occurs in approximately one in every million births, making it “ultra-rare,” with only around 20 sufferers in the UK.

Sufferers miss a liver enzyme that converts glycogen, the stored form of glucose, into the usable glucose their body needs to function.

This means they can develop profound hypoglycaemia, low blood sugar, very quickly. Prior to cornstarch therapy, GSD1b was universally fatal.

Catherine was born in June 2012, but aged six months, Jason and Maria noticed she was slightly different: her growth was slow, her arms and legs thin, and her tummy swollen.

Doctors said they were “worrying too much,” but aged 18 months, nursery staff raised her small size and prominent stomach as a red flag.

Jason recalled: “They said ‘she’s a lovely child, but there’s a problem. Something doesn’t seem right’. But again doctors just reassured us – with Catherine’s substantial nosebleeds dismissed as her picking her nose.”

It was only during a family trip to Disneyland Paris in August 2014, when Catherine suffered a high fever and visited a French hospital, that medics raised the alarm.

Eyewear retailer Jason said, “I remember about 10 or 15 doctors quickly becoming involved after they recognised that her liver was enormous.

“The following days were terrifying. Catherine had a full-body CT scan, an MRI, X-rays, a liver ultrasound, a lumbar puncture and a bone-marrow biopsy.

“At one stage, we were told she might have a condition, meaning she did not have long to live. I was totally broken.

“I remember having to call my parents to tell them that their granddaughter was going to die. It was like being hit with a sledgehammer.”

French medics eventually suspected an unusually severe viral infection but remained deeply concerned with Catherine’s liver being 11cm larger than it should have been.

In December 2014, visiting nursery worker Maria’s family in Spain, they met paediatrician Dr Carlos Ochoa, who suspected GSD, which was finally confirmed just three months before Catherine’s third birthday on the children’s liver ward at London’s King’s College Hospital.

Jason said: “It was horrifically traumatic. You never expect these things in your life. We were put on the liver ward and were seeing children dying.

“Across from Catherine was a little boy whose skin became more yellow in front of us. At night, his mother cried and sang lullabies to him. The fear and helplessness of that ward have never left me.

“You never understand until you’re in it and this isn’t just about my daughter and her disease. There are so many people with rare genetic diseases who take years to get a diagnosis.

“Because of how the NHS is set up it’s like a conveyor belt of mainstream illnesses that they can deal with, but they are not looking at other things. They are not looking outside of the box and that’s what is fundamentally holding the NHS back in a lot of ways.”

Doctors in the UK put Catherine on a plan of precisely-timed glucose-mix via a feeding tube pumped into her stomach overnight and injected in every two hours during the day.

But the reality of constant vigilance that the pump was still running, the feed was not leaking and the tube had not moved took its toll on the family.

Jason said: “We moved her bed beside ours so we could watch her while she slept. Changing it was traumatic. Catherine would cry and scream while we restrained her and forced another tube through her nose.

“One night, at around four o’clock in the morning, the connection between Catherine’s feeding tube and the giving set began to leak. It took around an hour to bring the situation under control.”

The exhausted parents began looking at other ways to manage Catherine’s condition and found a doctor in Spain who also suffers from GSD.

She recommended a carefully measured dose of uncooked cornflour mixed with cold water, which they fed to her in a tiny doll’s cup.

Unless she swallows the cornflour every four hours she could develop hypoglycaemia, which can prove fatal.

Jason said: “The cup was small enough to hold against her mouth while she was half asleep. I would mix the cornflour, lift her from bed and try to persuade a frightened, distressed and disorientated little girl to drink the very thing helping to keep her alive.”

The strict regime meant Catherine could play like a normal child and get dressed without worrying her tube would become dislodged.

In 2015 the family made the difficult decision to relocate to Spain permanently so Catherine could benefit from “better metabolic management, international expertise and newer treatments”.

Now they have a near military regime of feeds and supplements, meaning whether Catherine is staying with mum Maria or nearby at her dad’s home – as the couple have divorced but still co-parent – they must wake her in the night to drink her cornflour mix.

Jason explained: “It’s carefully measured, so it lasts exactly the right time, but it’s basically the same stuff you use to make gravy.

“One analogy would be if you’re pumping in glucose you’re running your body at high revs like a sports car but if the glucose suddenly stops the body crashes.

“That’s where there’s been a lot of deaths with the children – they’ve been on the overnight feeds, there’s been a problem with the pump breaking down, the parents didn’t notice and then the child went into coma and died.

“Giving cornflour instead is like as tractor, it just keeps the body chugging along.”

Catherine also cannot have milk or dairy products, fruit, sweets or chocolate – so when her friends pop out for an ice cream she must watch on.

Although GSD1b is a genetic condition, luckily her sister Elizabeth, 16, and brother Arthur, seven, don’t have it.

But the family are desperate to not only raise awareness of GSD but urge pharmaceuticals to keep seeing if existing drugs can be repurposed – like Catherine’s drug empagliflozin – to be a miracle treatment for other rare diseases.

Jason added: “Rare diseases are often very specific disruptions of fundamental biological processes. So studying them can teach researchers how existing medicines can be repurposed.”

Last week American dad Phil Schneider, whose teen daughter Sylvi has GSD1b, and pal Toby Schmidt completed a 10-day, 1,000km ride across the Alps to highlight the plight of families attending treatment alarms every four hours.

To donate to their cause – for GSD charity Sophie’s Hope – visit https://ridegsd1b.funraise.org/