Sensory toys for babies are crucial in the first year of life, aiding in their…
Autism spectrum disorder (ASD) is a complex developmental condition that affects how people communicate, interact, behave, and learn. It is called a “spectrum” disorder because there is a wide variation in the type and severity of symptoms that people with autism can have. Two big questions that often come up when discussing autism are – are you born with it or does something cause it later in life?
Let’s take a closer look at what the research says so far.
The Genetic Link
One of the strongest scientific indications that autism may be something you are born with is its heritability. Studies of twins have found that identical twins, who share nearly 100% of the same genes, are far more likely to both have autism compared to fraternal twins who only share around 50% of the same genes.
Research has identified a number of genetic mutations and variants associated with autism, such as changes in certain genes involved in brain development and functioning. However, most cases of autism are not linked to one single gene but rather complex interactions between multiple genes and other factors. This is why even identical twins don’t always share an autism diagnosis. Overall though, the inheritability factor indicates autism likely has strong genetic roots.
People with autism tend to show differences in development from early in life, even as infants. While symptoms may not fully manifest until toddlerhood, some subtler early signs can include:
- Reduced eye contact/engagement
- Less facial expression
- Delayed babbling/speaking
- Difficulty self-soothing
- Unusual reactions to sensory stimuli
Studies of home videos of children later diagnosed with autism also detect differences in social-communication behaviors like pointing, showing, and gaze shifting by 12 months of age. This suggests autism involves early atypical development of the brain and nervous system.
Brain Structure and Function
A number of structural and functional differences have been found in the brains of people with autism, even in early childhood. Some key areas affected include:
- Frontal and temporal lobes (involved in social-communication skills)
- Amygdala (processing emotions)
- Hippocampus (memory and learning)
- Corpus callosum (connecting the hemispheres)
People with autism tend to have more densely packed neurons in certain brain regions but weaker connections between different areas. There also tend to be differences in the release and activity of neurotransmitters like serotonin, dopamine, and oxytocin.
These kinds of biological differences point to autism originating very early in fetal brain development. The changes are present from birth, even if the outward symptoms emerge later.
So while autism seems primarily genetic and biological in origin, researchers are still studying a variety of environmental risk factors that may play a role by influencing biological development before and after birth. These may include:
- Advanced parental age
- Pregnancy/birth complications
- Exposures to heavy metals and pollution
- Viral infections in the mother during pregnancy
- Medications taken during pregnancy
However, the links with environmental triggers remain complex and uncertain. Most experts believe that autism cannot be entirely explained by environmental factors alone. Rather, autism likely arises from a combination of genetic susceptibilities and environmental influences on the developing fetus and baby.
Current scientific evidence strongly suggests that autism spectrum disorder is a condition that individuals are born with and manifests early in development. The exact causes are multidimensional, but autism primarily involves genetic factors that lead to differences in brain structure and neurological functioning even before birth.
Environmental factors may play a role by interacting with existing genetic vulnerabilities during key developmental stages. But they are unlikely to be direct original causes of autism on their own.
While more research is still needed, the evidence so far indicates autism originates very early on, possibly even prenatally, as a result of biological and genetically rooted developmental differences in the brain. Understanding these complex roots of autism spectrum disorder is crucial for developing better interventions and supports for people with autism to reach their full potential.
Frequently Asked Questions
Here are answers to some common questions people have about whether autism is something you’re born with or caused by external factors.
What causes autism spectrum disorder?
The exact causes of autism are still not fully understood, but research indicates it likely arises from a complex combination of genetic and environmental factors influencing early brain development. Differences in brain structure and neurotransmitter systems are present at birth. This suggests autism has strong biological and genetic origins.
Are you born with autism or does something trigger it?
The current scientific evidence strongly implies that autism is present from birth, even if behavioral symptoms don’t appear until toddlerhood. Various genetic factors and congenital differences in brain development are thought to be the primary underlying causes, rather than something that is triggered later.
Does genetics play a role in causing autism?
Yes, genetics plays a major role. Autism has high heritability, meaning it runs strongly in families. Specific genetic mutations associated with autism have been identified. Overall, autism is linked more to complex interactions of multiple genes rather than one single “autism gene.”
Can environmental factors cause autism?
Environmental influences like parental age, infections, or chemical exposures are unlikely to directly cause autism on their own. However, they may impact early fetal/child development to increase risk in those already genetically predisposed. More research is needed on these potential environmental risk factors.
Are children with autism born differently?
In many cases, yes. Subtle developmental differences like reduced eye contact or delays in early communication/language skills are detectable in infancy. Structural and functional brain abnormalities are also present from very early in life. This indicates autism arises during prenatal development.
Why do some identical twins have autism while their twin doesn’t?
This comes down to the complex genetics of autism. Identical twins share nearly 100% of genes, yet one twin may have autism while the other doesn’t. This demonstrates that while autism is highly heritable, there are likely multiple genes involved, not just one cause. Environmental factors may also come into play.
Can autism develop later in childhood?
In most cases, no. While autism may not be recognizable until social demands exceed limited capacities, in retrospective studies early subtle signs were nearly always present. Sudden onset of autism that wasn’t there in infancy would be very rare and require other explanations.
Does the MMR vaccine cause autism?
No, there is no scientific evidence that the MMR vaccine causes autism. Large epidemiological studies have consistently shown no link between receiving the MMR vaccine and developing autism. Autism symptoms also don’t correlate with when the vaccine is given.
Can natural treatments or diets cure autism?
There are no “cures” for autism, since it originates so early in brain development. But supportive therapies and teaching strategies can improve communication, behavior, and quality of life. Dietary approaches may relieve certain symptoms but don’t cause core autism symptoms to disappear.
When are you most likely to first notice signs of autism?
Many children with autism show clear symptoms like delayed speech by 18-24 months. Early red flags can include lack of babbling, reduced pointing, poor eye contact, and not responding to their name. But milder cases may go unnoticed until social demands increase around ages 3-4.