‘I’m watching my child fade away every single day, and it’s enough to break a person,’ says Georgia Nonas, 29. Her son, Cody, eight, has Sanfilippo syndrome – a rare genetic disorder often called childhood dementia – and every day brings another small loss. Georgia, now a full‑time carer, describes the grief as a ‘gut punch at random times in the day’. She talks of ‘anticipatory grief’ – the mourning that begins the moment a life‑limiting diagnosis is delivered. ‘You start grieving your child the day you get that diagnosis,’ she says. Child Bereavement UK, which offers confidential support to families, notes that parents who discover their child is not expected to live often experience shock, distress, numbness and denial. For Georgia, that reaction was immediate.
Cody was three years old when doctors confirmed he had Sanfilippo syndrome type A – the most aggressive form of the disease. The diagnosis followed years of worrying signs. At the age of one, he had recurrent ear infections and hearing difficulties – common early indicators, though at the time the family had never heard of the condition. Then came the regression. ‘He said “mamma” and “baba”, and then never spoke again,’ Georgia recalls. At two, Cody was diagnosed with autism – a label that later gave way to the true, devastating explanation. Georgia, sitting in the room with Cody’s father Callin and her own mother, describes the moment as ‘the worst day of my life’. ‘It was silent,’ she says. ‘I didn’t process it for a long time.’ Days later, at a family barbecue, she was unable to hold a conversation. ‘It was like in the movies when all you hear is ringing in your ears.’
Sanfilippo syndrome – medically termed mucopolysaccharidosis type III (MPS III) – is an inherited disorder that affects about one in every 70,000 births, though underdiagnosis may make that figure an underestimate. It is caused by a deficiency in specific enzymes responsible for breaking down complex sugar molecules called glycosaminoglycans (GAGs). Without those enzymes, the waste products accumulate inside the body’s cells, causing progressive damage, especially to the brain and spinal cord. Cody’s body is missing one such enzyme. ‘Over time, the damage caused by the waste takes away his ability to communicate, eat, and walk, and it causes brain damage,’ Georgia explains. Symptoms typically emerge between the ages of one and four, often after a period of normal development. Along with developmental regression, children commonly display coarse facial features, heavy eyebrows, full lips, excessive hair growth, sleep disturbances, respiratory problems and gastrointestinal issues such as frequent diarrhoea. Between 7,000 and 19,000 people globally are thought to have the condition, with researchers estimating one case per 50,000 to 250,000 people.
Cody also has epilepsy, another frequent symptom of the syndrome, and relies on daily painkillers for muscular and joint pain as well as a sleeping aid. His mobility, communication and even eating are affected. ‘Daily life can be hard for Cody,’ Georgia says. The disease is progressive: over months and years, children lose skills they once mastered. Types A and B – which account for most cases – typically lead to death in the teenage years; for type A the mean age at death is around 15 years, with pneumonia and respiratory infections the most common causes. Type C can progress more slowly, allowing some individuals to live into their early thirties. Georgia is acutely aware of the clock. ‘I don’t want birthdays to be a sad day, a reminder of the clock ticking,’ she says.
A race against time: the hope of gene therapy
In the United Kingdom, there is currently no approved disease‑modifying treatment for Sanfilippo syndrome. Management is limited to palliative care and symptom relief. But the family’s hope rests on a gene therapy developed by the US pharmaceutical company Ultragenyx, known as UX111 (rebisufligene etisparvovec). This one‑time intravenous infusion is designed to introduce a functional copy of the defective gene into the patient’s cells, enabling the production of the missing enzyme. Clinical trials have shown it can slow or halt neurodegeneration and preserve cognitive and motor function. The US Food and Drug Administration (FDA) has accepted a resubmitted Biologics License Application for UX111 and is expected to make a decision by 19 September 2026. The FDA had previously issued a Complete Response Letter in July 2025 citing manufacturing and control concerns, which Ultragenyx says it has now addressed. If approved, UX111 would be the first authorised treatment for Sanfilippo type A anywhere in the world.
Georgia is clear that the therapy is not a cure. ‘It isn’t a “cure” in the traditional sense, but it is a way to slow down the clock,’ she says. ‘Our biggest wish is to get him to that treatment so we can hold onto the boy he is today for as long as possible – to keep his smile, his laugh, and his spark from being taken away too soon.’ The family is fundraising to cover the substantial costs of travelling to the United States for treatment should the FDA give the green light. Meanwhile, other gene therapies are in development. Orchard Therapeutics has developed OTL‑201, which has shown promise in a UK proof‑of‑concept study, with some patients gaining cognitive skills. It has been granted an Innovation Passport designation under the UK’s Innovative Licensing and Access Pathway, which aims to accelerate access to promising medicines.
Despite the uncertainty, Georgia is determined to make memories. A trip to Disneyland Paris is booked for July. ‘I just want to make as many memories as possible,’ she says. She shares Cody’s story on social media in the hope that other parents might recognise the early signs – the coarse features, the heavy brows, the unexplained regression – and push for an earlier diagnosis. ‘Before his diagnosis, we had never heard of it,’ she says. ‘If someone sees Cody’s story and thinks, “Oh, my child has those features”, it can lead to an earlier diagnosis – which is so important so we can get them support and therapies.’ In the UK, the MPS Society, Childhood Dementia Scotland, the Team Sanfilippo Foundation and the Cure Sanfilippo Foundation all offer resources and support for families affected by the condition.
For Georgia, every day is a balancing act between love and grief. ‘Everyone who meets him is just amazed by him, and I couldn’t be prouder to be his mama,’ she says. ‘When Cody was diagnosed we lived in a world with very little hope, however in the coming years, we’re very focused on time.’ She describes the boy she still has: a ‘loving little boy’ with ‘the most contagious smile’. And she clings to the possibility that the therapy, if it comes, will give them more of that time together.