A toddler with a rare inherited condition has become the first child to be treated by the NHS with a new life-saving gene therapy.
Teddi Shaw was diagnosed in time because her older sister Nala showed symptoms – but it was too late to treat Nala, who is now terminally ill.
Both girls have MLD, which severely damages the brain and nervous system.
The one-off treatment, called Libmeldy, costs £2.875m and is the most expensive medicine ever approved for the NHS.
The BBC was given exclusive access to follow Teddi’s treatment over several months and spoke to other families affected by MLD.
Imagine having two daughters with a devastating genetic condition – but only one can be saved.
Three-year-old Nala – and Teddi, who is 19 months old – both have MLD, metachromatic leukodystrophy.
Children with this fatal genetic disease are born apparently healthy, but MLD gradually attacks the brain and body.
Before Nala became ill, she was a completely normal toddler.
“She was always singing, dancing and spinning around everywhere, always laughing – just a cheeky little girl,” says her dad, Jake.
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Watch: 19-month-old Teddi is the first child to be treated on the NHS with the new gene therapy
But just over a year ago, Nala’s walking gradually became uneven and she started falling over more often. She was also showing signs of a tremor.
Her parents Ally, 32, and Jake, 29, became increasingly concerned. Ally was convinced Nala had a brain tumour.
Initially, doctors reassured them nothing was wrong. But then, in April last year, Jake and Ally took Nala to A&E where she had an MRI scan. Forty-five minutes later they had a likely diagnosis.
“When the doctor said ‘It’s not a brain tumour,’ I was doing cartwheels almost, so excited,” Ally says.
But her relief evaporated when the doctor mentioned metachromatic leukodystrophy – which they had never heard of before. When she left the room, Jake Googled the term. “I could tell by his face it wasn’t good news,” says Ally.
MLD is caused by a faulty gene which means children affected cannot produce an important enzyme called ARSA – a protein that helps the body’s metabolism work.
As a result, fatty chemicals called sulfatides build up. These gradually destroy the protective layer around cells in the brain and nervous system, leading to a devastating deterioration. Children lose the ability to walk, talk or eat – and eventually to see or hear.
Because both Ally and Jake are carriers of the faulty gene, they were told Nala’s younger sister Teddi had a one-in-four chance of also having MLD.
“I thought to myself, it can’t happen again, we can’t be that unlucky,” says Jake. “When we found out, it was just heart-breaking.”
But for 10-month-old Teddi, there was hope. The disease had not yet affected her and so she became the first patient treated on the NHS with Libmeldy, which must be given before the disease has caused irreparable damage.
Nala’s MLD was identified too late for her to be treated. She is already unable to walk or talk, and has to be tube-fed.
“When they told us there was treatment available for Teddi it was kind of a bitter pill to swallow because Nala can’t be helped,” says Ally.
She says they are sad and “extremely grateful” at the same time.
“I’ve always said Nala saved Teddi’s life. And that’s how I wanted to think about it,” says Jake.

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Ally watches while Teddi’s stem cells are removed
Libmeldy involves altering a patient’s own cells to correct the faulty gene. In June 2022, Teddi was hooked up to a machine at Royal Manchester Children’s Hospital where blood was removed and filtered, so a single bag of stem cells could be collected. The process looks similar to dialysis.
The cells were then sent to Milan, where scientists used a harmless virus to insert a working version of Teddi’s faulty gene – the one which should produce her missing enzyme – back into the stem cells. The gene-corrected stem cells were then sent to Manchester to be infused back into Teddi.

Teddi and her mum moved into hospital for the duration of the treatment while Jake, a carpenter, was home in Northumberland looking after Nala.
Before she could be given the replacement cells, Teddi had to have chemotherapy to kill off the remaining faulty stem cells in her bone marrow.
In August, we were back in Manchester to watch Teddi receive Libmeldy.
In her hospital room, Teddi, then 14 months old, had chosen that day to attempt her first tentative steps. Mum Ally said her younger daughter was taking it all in her stride.
“She’s doing absolutely fine, considering what she’s been through,” Ally told us. “She’s still just her mischievous normal little self.”
The infusion of Libmeldy took less than an hour. Over the following days the gene-altered cells migrated to Teddi’s bone marrow and began producing the enzyme she had been missing since birth. What is remarkable is that this is a one-off treatment, with the hope that it provides a permanent fix for MLD.