Imagine knowing in your 20s or 30s that you carry a gene which will cause your mind and body to slowly unravel. Huntington’s disease is inherited, relentless and fatal, and there is no cure. Families live with the certainty of decline stretching across generations.

Now, a new treatment is being widely reported as a breakthrough.

Last week, gene therapy company uniQure announced that a one-time brain infusion appeared to slow the disease in a small clinical study.

If confirmed, this would not only be a landmark for Huntington’s disease but potentially the first time a gene therapy has shown promise in any adult-onset neurodegenerative disorder.

But the results, which were announced in a press release, are early, unreviewed and based on external comparisons. So, while these findings offer families hope after decades of failure, we need to remain cautious.

What is Huntington’s disease?

Huntington’s is a rare but devastating disease, affecting around five to ten people in 100,000 in Western countries. That means thousands in Australia and hundreds of thousands worldwide.

Symptoms usually start in mid-life. They include involuntary movements, depression, irritability and progressive decline in thinking and memory. People lose the ability to work, manage money, live independently and eventually care for themselves. Most die ten to 20 years after onset.

The disease is caused by an expanded stretch of certain DNA repeats (CAG) in the huntingtin gene. The number of repeats strongly influences when symptoms begin, with longer expansions usually linked to earlier onset.

Looking for a treatment

The gene that causes Huntington’s disease was identified in 1993, 32 years ago. Soon afterwards, mouse studies showed that switching off the mutant huntingtin protein even after symptoms had begun could reverse signs and improve behaviour.

This suggested lowering the toxic protein might slow or even partly reverse the disease. Yet for three decades, every attempt to develop a therapy for people has failed to show convincing clinical benefit. Trials of huntingtin-lowering drugs and other approaches did not slow progression.

What is the new treatment?

The one-time gene therapy, called AMT-130, involves brain surgery guided by MRI. Surgeons infuse an engineered virus directly into the caudate and putamen brain regions, which are heavily affected in Huntington’s.

The virus carries a short genetic “microRNA” designed to reduce production of the affected huntingtin protein.

By delivering it straight into the brain, the treatment bypasses the blood–brain barrier. This natural wall usually prevents medicines from entering the central nervous system. That barrier helps explain why so many brain-targeted drugs have failed.

What did they find?

Some 29 patients received treatment, with 12 in each group (one low-dose, and one high-dose) followed for three years. According to uniQure, those given the higher dose declined much slower than expected.

The study compared how much participants’ movement, thinking and daily function declined, compared to a matched external group from a global Huntington’s registry (meaning they weren’t part of the study). The company claimed those given the higher dose had a 75% slowing in their decline.

On a functional scale focused on independence, the company reported a 60% slowing in decline for the higher dose group.

Other tests of movement and thinking also favoured treatment. Nerve-cell damage in spinal fluid was lower for study participants than would be expected for untreated patients.

Why should we be cautious?

These findings are an early snapshot of results reported by the company, not yet peer-reviewed. The study compared treated patients to an external matched control group, not people randomised to placebo at the same time. This design can introduce bias. The numbers are also small – only 12 patients at the three-year mark – so we can’t draw solid conclusions.

The company reports the therapy was generally well tolerated, with no new serious adverse events related to the drug since late 2022. Most problems were related to the neurosurgical infusion itself, and resolved. But in a disease that already causes such severe symptoms, it is often hard to know what counts as a side effect.

The company uniQure has said it plans to seek regulatory approval in 2026 on the basis of this dataset.

Regulators will face difficult decisions: whether to allow access sooner before all the questions and uncertainties are addressed – based on the needs of a community with no effective options – and wait for further data while people are being treated, or to insist on larger trials that confirm results before approval.

What does it mean?

If upheld, these results represent the first convincing signs that a gene-targeted therapy can slow Huntington’s disease. They may also be the first evidence of benefit from a gene therapy in any adult-onset neurodegenerative disorder. That would be a milestone after decades of failure.

But these results do not prove success. Only larger, longer and fully peer-reviewed studies will show whether this treatment truly changes lives. Even if approved, a complex neurosurgical gene therapy may not be easily accessible to all patients.

The company has said the drug’s price would be similar to other gene therapies – which can cost over A$3 million per patient – and will have the added cost of brain surgery.

The takeaway

For families who carry this gene, the hope is profound. But caution is just as important.

We may be witnessing the first credible step toward slowing an inherited adult-onset neurodegenerative disease, or just an early signal that may not hold up.

Ultimately, only time and rigorous science will show whether this treatment delivers the benefits so urgently needed.

Bryce Vissel, Cojoint Professor, School of Clinical Medicine, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

To recover from abuse or another traumatic experience, some people turn to a therapy called eye-movement desensitisation and reprocessing, or EMDR.

But this may present problems if these people pursue justice in the courts. In New South Wales, for instance, evidence obtained using EMDR can’t be used in a case unless it has been approved by the director (or deputy) of public prosecutions.

Prosecutors are concerned that after EMDR, trauma memories can’t be relied on as valid testimony. This has resulted in court cases not proceeding.

But what does the evidence say?

What is EMDR?

EMDR is one of the common exposure-based treatments for post-traumatic stress disorder (PTSD).

This group of therapies – which encompass prolonged exposure, cognitive processing therapy, EMDR and other variants – all ask a patient to recall their trauma. The therapists integrates this information and aims to correct unhelpful thought patterns that may be prolonging their distress.

Each of these treatments is recommended in most international guidelines for treating PTSD.

EMDR is different from the other exposure-based therapies because the therapist also asks the patient to move their eyes in a rapid side-to-side movement. This will typically involve following the therapist’s fingers move back and forth.

Proponents of EMDR initially proposed eye movements triggered neural processes that help people better adjust to or process trauma memories. However, the actual role of eye movements has been subject to much debate.

Although the mechanism isn’t yet fully understood, the weight of evidence suggests eye movements may reduce distress while recounting trauma memories because it depletes our working memory capacity. This results in less focus on the negative emotions associated with the memory.

Where did concerns about EMDR affecting memories come from?

EMDR has been criticised for potentially distorting people’s memories of traumatic events dates since the 1990s when the treatment increased in popularity.

This was also a period when when a controversial movement of “recovered memory therapies” emerged. These were used to guide people to reconstruct memories that were purportedly “hidden” or “repressed”.

This involved therapists directing patients to focus attention on internal states, suspend reality and allow themselves to be guided by the therapist to recover so-called “repressed memories”, often of satanic or ritual abuse.

In the wake of this movement, many studies showed this sort of guided intervention could lead to false, or even implanted, memories.

At the same time, researchers were concerned about hypnotic techniques. During hypnosis, people could reconstruct false memories. They were particularly susceptible to misleading information and had stronger confidence in these memories.

For this reason, authorities around the world cautioned against using hypnosis in cases that may involve the person subsequently needing to give testimony in legal proceedings.

Some likened EMDR to hypnosis, others were sceptical of its claims

Some agencies and experts considered EMDR a hypnosis-like intervention because it focused the person’s attention on their internal state, promoted increased absorption in memories and actively guided memories.

Many also likened the finger waving in front of the patient’s face as inducing a hypnotic state.

Because EMDR guided patients to process memories in a way that made them less distressing, some concluded EMDR-elicited memories were comparably susceptible to distortion as hypnotically-induced memories.

This perception of EMDR at the time may also have been influenced by much initial scepticism of the therapy.

In the early period of its popularity, EMDR proponents made excessive claims of its success, such as being able to completely resolve trauma memories in a single session, despite the lack of evidence.

What does the evidence actually say?

It’s difficult to test the claim that EMDR increases the likelihood of false memories because you can’t readily study this in clinical settings.

Instead, researchers have used experimental designs in people without PTSD to determine if eye movements themselves are likely to lead to false memories. The results are mixed.

Multiple studies have shown eye movements can lead to false memories. One study showed healthy research participants a video of a car accident. Half the sample then used eye movements. Then all participants were read an eye-witness narrative that involved false information about the video.

This study found those who used eye movements were more susceptible to the misinformation. It seems this effect may occur because eye movements reduce the vividness and intensity of emotions in memories, thereby making them more susceptible to false memories.

However, other laboratory-based studies have not replicated this effect. One study using the same design found using eye movements didn’t make memory more likely, reduce correct memory details, or affect the vividness or emotional intensity of the memory.

What does this all mean?

EMDR is one of a suite of exposure-based treatments for PTSD that involve recounting trauma memories and integrating new information about the trauma. These appear to be key in helping people resolve their traumatic stress. Although EMDR is not better than other exposure-based treatment, it is as effective as the others.

Although some evidence points to eye movements making a person more susceptible to false memories, other studies do not find this. Importantly, these studies are not actually testing EMDR.

There is no direct evidence that EMDR leads to false memories, just as there is no evidence that prolonged exposure or other exposure-based treatments do. Singling EMDR out as being particularly susceptible to memory distortion doesn’t appear to be supported by the scientific evidence.

The position of legal authorities to not accept testimony following EMDR is therefore not justified and may deny trauma survivors the right to legal proceedings.

If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14. The National Sexual Assault, Family and Domestic Violence Counselling Line – 1800 RESPECT (1800 737 732) – is also available 24/7 for any Australian who has experienced family violence or sexual assault.

Richard Bryant, Professor & Director of Traumatic Stress Clinic, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.