While Asperger’s is no longer used as a clinical diagnosis — as of 2013, the American Psychiatric Association classifies Asperger’s as part of the autism spectrum disorders — the terminology is still commonly used. And as with most autism spectrum disorders, researchers aren’t able to pinpoint one specific cause of Asperger’s. But they do have some theories.
Genes, brain changes, and environment likely all play a role in this disorder.
Additionally, certain risk factors can increase the chance of developing Asperger’s.
What Are the Possible Causes of Asperger’s Syndrome?
Many studies have looked at possible causes for autism spectrum disorders like Asperger’s. Some have provided clues that help doctors identify potential triggers.
Genes appear to affect a person’s chances of developing Asperger’s. While no one specific gene has been found to cause Asperger’s, the disorder seems to run in families. (1)
For example, younger siblings of a child with Asperger’s are at a greater risk of developing the syndrome than other kids. Studies on identical twins have shown that if one twin has an autism spectrum disorder, the other is likely to be affected between 36 and 95 percent of the time. (2)
Additionally, certain genetic conditions, such as Fragile X syndrome and Rett syndrome, are linked to the development of Asperger’s. Fragile X syndrome is the most commonly known single-gene disorder and accounts for about 2 to 3 percent of all autism spectrum disorders. (3)
Spontaneous gene mutations, or gene changes that happen for unknown reasons, may also influence a child’s risk of developing Asperger’s.
Scientists continue to study how genes are related to Asperger’s. They hope to provide more answers to help better explain this complex connection.
Imaging studies of people with autism spectrum disorders have shown differences in certain parts of the brain, especially in the areas known as the frontal and temporal lobes.
Researchers are working to figure out whether these changes are due to gene abnormalities, damage during pregnancy or birth, an injury during the first few months of life, or a combination of several factors. (2)
Many experts believe environmental triggers may be a culprit for Asperger’s.
While more research needs to be done, some have theorized that certain issues during pregnancy may increase a baby’s risk of developing an autism spectrum disorder. Some possibilities include:
- An expectant mother having a viral infection
- Birth complications
- In utero exposure to chemicals, such as phthalates or pesticides
- In utero exposure to air pollutants
It’s important to note that many children who are exposed to these risks never develop Asperger’s or another form of autism. (5)
What Doesn’t Cause Asperger’s: Debunked Myths
You might have heard that vaccines are linked to autism, but this claim is unproven. On the contrary, extensive research has shown there is no link between vaccines and autism spectrum disorders.
Years ago, one controversial study that caused concern over the association between vaccines and autism was withdrawn because of its poor design and questionable methods. (5)
The Centers for Disease Control and Prevention (CDC) says that vaccines are safe and do not cause autism. (6) In fact, skipping vaccines can put children at risk of contracting and spreading other dangerous diseases, such as measles, mumps, or pertussis (whooping cough).
Another common myth is that Asperger’s is caused by a poor home environment. Research shows the disorder is not due to a lack of love, emotional trauma, or neglect.
Boys Are at Higher Risk for Asperger’s Than Girls
Boys are about 4 times more likely to develop an autism spectrum disorder, and according to some studies, up to 11 times more likely to develop Asperger’s syndrome compared with girls. (7)
Researchers aren’t sure exactly why boys are at a higher risk. Studies have suggested links between male fetal testosterone levels and autism spectrum disorders.
Some experts have also proposed theories that girls are simply underdiagnosed or that they are better protected genetically. (8)
Other Risk Factors for Asperger’s Syndrome
Other risk factors for Asperger’s syndrome may include:
- Being born prematurely, especially before 26 weeks
- Being born less than a year apart from an older sibling
- A family history of Asperger’s
- Being born to older parents
- Having a mental health disorder, such as depression or anxiety
- Having another health condition, such as Tourette’s syndrome, epilepsy, or tuberous sclerosis (a condition that causes benign tumors to grow in the brain and other organs)
The Likely Answer: There’s No Single Cause
While the exact cause of Asperger’s isn’t known, many experts believe the disorder is probably triggered by a variety of factors. A combination of genetic, neurological, and environmental issues might work together to cause the syndrome.
For example, certain genetic mutations may make a child more sensitive to chemicals or other environmental causes. Or genes might be the reason specific brain changes happen in someone with Asperger’s. (9)
Experts are working to find out just how all the pieces of the puzzle fit together.
Can You Lower Your Child’s Risk of Asperger’s?
There’s no way to totally prevent Asperger’s or other forms of autism, but some research suggests certain measures may provide a layer of protection.
A 2014 study found that women who have pregnancies spaced two to five years apart have the lowest risk of having a child with an autism spectrum disorder. Kids conceived less than 12 months after their next-oldest sibling were 50 percent more likely to be diagnosed with autism compared with children conceived 24 months to 59 months after their next-oldest sibling. (10)
As a precaution, you might also want to avoid harsh chemicals, risky medication, and air pollutants during pregnancy. Also, getting vaccinated against the German measles (rubella) before you get pregnant may reduce your risk of having a child with an autism spectrum disorder.
If Asperger’s runs in your family, and you’re concerned about your child having the disorder, It might also be helpful to talk to a genetic counselor. This professional can help you better understand your risk of having a baby with Asperger’s. (2)