Potential breakthrough if experts discover a factor during pregnancy that they believe causes autism

Scientists have been grappling with the puzzle of the origins of autism for decades – now a study suggests that a bad cold or flu during pregnancy could be a cause.

They have shown that when the mother’s immune system is boosted in response to a viral infection, it can hinder the developing baby’s brain development.

Female embryos appeared to be protected from these effects, but according to research on mice, a third of male embryos were affected to some extent.

This is consistent with autism being more common in boys than girls, according to the team from Cold Spring Harbor Laboratory (CSHL) in New York.

Researchers have discovered that autism can develop while a fetus is in the womb. When a pregnant woman gets a bad cold or flu, her immune response can trigger a neurological reaction in the baby’s brain

Researchers simulated a viral infection in mice and monitored the fetus’s response to how the mother’s immune system responded to a cold or flu virus, known as maternal immune activation (MIA).

MIA is activated when the immune system kicks into high gear, increasing levels of cytokines and chemokines that can cross the placenta and the baby’s blood-brain barrier.

Chemokines fight the flu by moving other immune cells, such as cytokines, to the site of the infection.

Cytokines are small immune cells that fight harmful pathogens by calling on other immune cells, causing symptoms such as fever, runny nose and body aches.

Because a fetus’s brain is so sensitive to environmental cues in the womb, this response can cause a wide range of behavioral problems, including social disabilities such as autism spectrum disorder.

Irene Sanchez Martin, a postgraduate student at CSHL, said her recent experiments with mice showed that when the mother contracted a virus, the embryo’s brain development slowed.

“The difference in my work is that I monitor what happened to the fetus 24 hours after exposure to the maternal inflammation, rather than analyzing the behavior of the offspring as adults,” she said.

Autism is on the rise in the US: an estimated one in 36 eight-year-olds will be diagnosed in 2020, up from one in 150 in 2000

Sanchez Martin focused on how prenatal inflammation caused by a cold or flu affected the brain of the developing fetus.

Her work did not look at other factors that cause mothers’ immune systems to go into overdrive, such as in response to a vaccine, obesity or underlying conditions.

However, established global studies have shown that many vaccines actually protect against childhood diseases by passing antibodies from the mother to the fetus before it is born.

Flu vaccines work differently than the active disease because it forces the body to produce antibodies that prime the autoimmune system so it doesn’t cause inflammation and other symptoms.

Santhosh Girirajan, an associate professor at Pennsylvania State University who studies the genetic underpinnings of neurodevelopmental disorders, said NBC News: ‘We have known for years that vaccines do not cause autism.’

Prenatal inflammation is thought to affect how the growing baby’s brain organizes the neural networks that connect cells and synapses.

If these are disrupted, the number of neurons and synapses in the brain can decrease, which has been linked to the development of autism in humans.

One of the major breakthroughs from Sanchez Martin’s research showed that although female embryos appeared to be protected from the MIA, about a third of male embryos showed signs of a deficit in brain development consistent with autism.

Data has shown that autism is more common in men than women: in the US, four in 100 boys and one in 100 girls have the disorder.

Additional research is still needed to unravel the link between the immune system’s response to a virus and its impact on the fetus.

More than 5.4 million people in the US are currently diagnosed with autism and 40 to 80 percent are likely related to genetics, but that still means 20 to 60 percent are caused by other factors.

Early diagnosis is crucial in autism because there are currently no treatments and it takes years to test and diagnose the disorder.

Sanchez Martin said her research is still in the early stages and more work needs to be done to definitively link cold and flu viruses to autism.

However, she is hopeful that future findings can help doctors recognize the early warning signs of autism before a child is born.

Autism among children is on the rise across the US, with the Centers for Disease Control and Prevention (CDC) reporting that in 2000 an estimated one in 150 eight-year-olds had autism.

But by 2020, that number had skyrocketed to one in 36 eight-year-olds.

The increase can be attributed to doctors becoming better at identifying cases of autism and becoming more aware of the disorder.