Study Links Little-Known Hormone to Autism

A recent study has suggested that a little-known hormone, crucial for social interactions, may have connections to autism.

Social challenges, especially in forming friendships and understanding conversation cues, are among the most recognizable signs of autism.

To delve into this connection, researchers from Spain genetically altered mice to introduce a mutation in their Shank3 gene. This gene is essential for maintaining the structure of synapses, which are the connections between brain cells.

Mutations in the Shank3 gene have been associated with various neurocognitive disorders, including autism and Alzheimer’s. However, the precise mechanisms behind this link have not been fully clarified.

The study found that mice with Shank3 mutations failed to release sufficient amounts of the hormone vasopressin.

While vasopressin regulates fluid balance and blood pressure, it also interacts with two receptor pathways—one linked to interpreting social cues and another related to aggression. These aspects are particularly challenging for many individuals with autism.

The researchers believe these findings provide the first evidence showing how genetic mutations affect social interactions in people with autism.

They also proposed that emerging drugs could target these receptors to stimulate vasopressin production, potentially enhancing social capabilities without increasing aggressive behavior.

It remains uncertain how these findings might apply to humans, but they could pave the way for new treatments aimed at improving social deficits associated with autism.

Dr. Félix Leroy, the lead author from the Institute of Neurosciences at Universidad Miguel Hernandez de Elche in Spain, mentioned that they managed to enhance sociability without escalating aggression, which is vital for future therapeutic considerations.

This research is relevant amidst rising autism rates in the US, with nearly one in 31 children diagnosed today compared to one in 150 in the early 2000s.

Experts largely attribute this increase to improved diagnostic practices and increased awareness of autism in previously overlooked groups, such as girls and adults.

Meanwhile, health secretary Robert F. Kennedy Jr. is initiating studies to investigate potential causes, proposing factors like pesticides, ultra-processed foods, and toxic metals might play a role.

Genetic mutations, like those in the Shank3 gene, have also been indicated in earlier studies as triggers for autism.

Recent investigations suggest that a significant portion—between 40 and 80 percent—of autism risk is genetic, with single gene mutations accounting for up to one in five cases.

The study, which was published in July in the journal Nature Communications, involved testing genetically modified mice in various behavioral scenarios, such as free roaming and one-on-one interactions.

It was observed that the modified mice displayed reduced typical social behaviors, such as exploring new environments or engaging with other mice, compared to their unaffected counterparts.

The researchers discovered that these mice had fewer neurons releasing vasopressin, which typically targets the lateral septum—a brain area essential for social behavior regulation, anxiety, and fear.

The results indicated that insufficient vasopressin reached the lateral septum in the modified mice, leading to reduced sociability and aggression. However, by manipulating individual receptor pathways, researchers could enhance social capabilities while keeping aggression in check.

This research has led to a patent application focused on creating drugs that can selectively activate receptors controlling sociability to address social deficits in autistic individuals without increasing aggression.

Additionally, since this vasopressin pathway is more developed in males, the researchers noted that this could help explain the higher prevalence of autism in males compared to females.

Data from the CDC shows that around 5 percent of boys are diagnosed with autism, compared to 1.4 percent of girls—highlighting a significant disparity.

Dr. Leroy emphasized that future treatments could be tailored to account for these differences.

Current medications that affect vasopressin production include tolvaptan and conivaptan, used mainly for low sodium levels and kidney conditions.