A little-known hormone that’s key for socialization could have links to autism, a study suggests.

Social difficulties like making friends and interpreting conversational cues are some of the most tell-tale signs of autism. 

To explore this link, researchers in Spain genetically modified mice to have a mutation in their Shank3 gene, which helps organize and maintain the structure of cell connections called synapses. 

Shank3 gene mutations have been linked to multiple neurocognitive disorders,  including Alzheimer’s disease and autism. However, the exact mechanism has largely been unclear. 

But the new study revealed mice with Shank3 mutations did not properly release adequate levels of the hormone vasopressin.

Vasopressin is responsible for regulating fluid balance and blood pressure. However, it also binds to two different receptor pathways: one that interprets social cues and another that causes aggression, both behaviors that autistic individuals often struggle with. 

The researchers believe the findings show the first evidence of how a genetic mutation causes issues with social interactions and regulations in people with autism. 

They also suggested that using in-development drugs to activate these receptors separately to produce vasopressin may improve socialization without triggering increased aggression.  

While it’s unclear how the findings would translate in humans, they could provide a first step into developing new treatments to alleviate autistic behavior deficits.

A new study suggests a little-known hormone in the brain could be responsible for social deficits in people with autism (stock image)

A new study suggests a little-known hormone in the brain could be responsible for social deficits in people with autism (stock image)

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Dr Félix Leroy, lead study author and researcher at the Institute of Neurosciences at Universidad Miguel Hernandez de Elche in Spain, said: ‘We managed to improve sociability without increasing aggression, which is fundamental if we are thinking about a future treatment.’

The findings come as autism is on the rise in the US, up to one in 31 kids compared to one in 150 in the early 2000s. 

Experts have largely blamed the increase on doctors getting better at diagnosing the condition and more attention being paid to previously overshadowed groups like girls and adults. 

However, health secretary Robert F Kennedy Jr has launched a series of studies to pin down a definitive cause, suggesting pesticides, ultra-processed food and toxic metals could be to blame. 

Genetic mutations, like those in Shank3, have also been shown in previous studies to trigger the condition.

Recent research suggests 40 to 80 percent of the risk of autism is genetic, and up to one in five cases are linked to mutations of single genes. 

The study, published in July in the journal Nature Communications, modified mice to have Shank3 mutations and had them undergo a series of behavioral and social tests, including free roaming, interacting one-on-one with other mice and having a new mouse introduced into their surroundings. 

Genetically modified mice showed a decrease in normal social behaviors like exploring their surroundings or interacting with other mice compared to those without genetic mutations. 

The researchers found genetically modified mice had fewer neurons that release vasopressin. These neurons typically release vasopressin into the lateral septum, an area of the brain responsible for regulating social behavior, anxiety and fear. 

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The findings suggests in mice with Shank3 mutations, little vasopressin actually reached the lateral septum, causing reduced sociability and less aggression, which is necessary in small amounts for mice to mark their territories. 

But by manipulating each receptor pathway separately, the researchers were able to improve socialization and aggression without making the mice too aggressive.  

The research is protected by a patent application aimed at developing drugs that can selectively activate the AVPR1a receptor, which controls sociability, to improve social deficits in autistic individuals without inducing aggression. 

Additionally, because this vasopressin pathway is more developed in males, the researchers said this could explain why autism is more common in males than females.

CDC data shows about five percent of boys are diagnosed with autism compared to 1.4 percent of girls, a 3.4-fold increase.  

Dr Leroy said: ‘Our results suggest that future treatments could be personalized, taking these differences into account.’ 

Current drugs that target vasopressin production include tolvaptan (Samsca) and conivaptan (Vaprisol), which treat low sodium and kidney issues.Â