Doctors discover new cause of autism: 'Fourteen times more likely'

Autism may be caused by a little-known genetic condition, experts say.

They've found children with myotonic dystrophy type 1 (DM1) are also 14 times more likely to develop autistic spectrum disorder.

DM1 is a disorder people inherit from their parents that causes progressive muscle weakness, fatigue, and a host of cognitive issues.

Experts believe it may also affect how the brain develops and processes information in early life, potentially altering neural pathways linked to communication, behavior, and social interaction — hallmarks of autism.

The discovery could help unlock part of the mystery around how autism develops, providing vital clues to its biological roots.

DM1 is caused by a faulty gene, and now researchers believe that gene may also play a role in autism.

The researchers said the findings are a step closer to understanding autism not just as a spectrum — but as something with specific, traceable origins.

And crucially, it raises hopes for more targeted support for patients with both conditions and treatment that focuses on repairing damaged genes.

However, the team also emphasized DM1 is significantly more rare than autism, and not everyone with DM1 will be diagnosed with autism.

In DM1, DNA strands in a gene called DMPK repeat, a process called tandem repeat expansions (TREs), causing the gene to not function properly.

For people with DM1, this leads to symptoms like progressive muscle weakness and involuntary movements.

The functional errors lead to protein imbalances affecting other genes responsible for brain function.

The researchers said these gene impairments may cause people with DM1 to develop signs of autism like repetitive movements, a lack of coordination and sensory issues.

While autism affects about 7million Americans, only about 140,000 are diagnosed with DM1.

The study authors, from the University of Nevada Las Vegas (UNLV), said the findings could make it easier to diagnose autism in people with conditions like DM1 and lead to treatments to repair the damaged genes.

Dr Ryan Yuen, study author and senior scientist in the Genetics & Genome Biology program at the Hospital for Sick Children in Las Vegas, said: 'Our findings represent a new way to characterize the genetic development of autism.

'By identifying the molecular pathway behind this connection, we can begin to investigate new approaches to ASD diagnosis and the development of precision therapies that release these proteins back into the genome.'

This means essential proteins sapped away from DNA could be added back, repairing faulty genes and preventing further errors from appearing.

Meanwhile, another new study from researchers in China found a non-invasive brain stimulation treatment may improve certain autism signs like trouble sleeping and issues with social interaction.

The treatment, called transcranial pulsed current stimulation (tPCS) involves sending electrical impulses through electrodes that are placed on a patient's scalp.

The signals coming through the electrodes are thought to increase brain activity in certain areas.

The team found children ages three to 14 who received 20 tPCS sessions over four weeks had 'significant' improvements in sleep, language, sensory issues and socialization.

Both studies come as the latest CDC data shows autism is on the rise in the US, affecting one in 31 children. This is a staggering increase from one in 150 in the early 2000s.

While many experts believe the rise is due to better screening and diagnostics, health authorities like Robert F Kennedy Jr believe environmental factors like pesticides, food additives and ultrasound scans could be to blame.

In the UNLV study, published in Nature Neuroscience, researchers analyzed RNA in 38 gene sets from people with and without autism. RNA is a key molecule that helps cells build proteins and function properly.

The team found that when the DMPK gene responsible for DM1 repeats, it creates 'toxic RNA' that binds to proteins involved in DNA production during brain development.

That 'toxic RNA' depletes the protein and prevents it from binding the other RNA molecules, causing a protein imbalance and errors in other surrounding genes.

Dr Yuen said: 'TREs are like a sponge that absorbs all these important proteins from the genome. Without this protein, other areas of the genome don’t function properly.'

The researchers noted both DM1, the muscle-weakening condition, and autism can both be caused by repetitions in the DMPK gene.

Dr Lukasz Sznajder, a research lead and assistant professor at the University of Nevada Las Vegas (UNLV), said: 'A variation really stood out to me that we see in rare neuromuscular disease.

'This is how we started connecting the dots. We found a molecular link, or overlap, which we believe is the core of causing autistic symptoms in children with myotonic dystrophy.'

DM1 leads to muscle weakness around the limbs and, as it progresses, vital organs like the heart and lungs. This leads to abnormal heart rhythms and breathing issues.

Symptoms typically appear in adolescence or young adulthood and start with weakness around the muscles in the face, neck, fingers and ankles.

The condition affects 140,000 Americans and the life expectancy is around 48 to 55 years.

The study authors said more research is needed connecting DM1 to autism, but the group is planning to look at if these DNA errors are occurring in other genes that have been associated with autism.