Is Autism Genetic?

Autism is a neurologically diverse spectrum disorder with many possible markers, from social differences to unique physical features. Many parents of autistic children feel concerned that their child has a disorder. Others may believe that their child is either not capable of everyday function, or is extraordinarily gifted and brilliant. In fact, autism is a wide-ranging category of behaviors and characteristics, and can be associated with high intelligence, irregularly distributed intellectual developmental disorder, or simply average intelligence with non-average ways of processing information. The ways that we assess children and adults should be respectfully individual-based and built on an awareness that neurodiversity is a valuable part of our world.

In the past, autism was thought to be a psychological illness, where parents and caregivers were often wrongly blamed for “causing” the child’s autism by not interacting correctly with their baby. That has been proven to be false. Autism (or Autism Spectrum Disorder, otherwise known as ASD) is now considered to be a biomedical condition with neurobiological causes, developed from inherited genes and/or gene mutations that arise spontaneously (de novo) in either the egg or sperm before conception, or during fetal development after conception.

Certain genetic syndromes, including Rett syndrome, Fragile X syndrome, Angelman syndrome, Prader-Willi syndrome, and schizophrenia, as well as epilepsy and seizure disorders, have been connected with autism.

Is autism genetic or environmental?

Research is underway to detect whether and how environmental factors including medications, viral infections, pollution, severe maternal stress, and pregnancy complications may comprise some of the contributing causes for Autism Spectrum Disorder. Schizophrenia specifically has been associated with inflammatory responses during pregnancy, due to exposure to an infection before birth, and this has also been shown to affect neuronal development in the fetus in a way that can also cause autism, as well as bipolar disorder. While environmental causes are thought to have some effect, after much research it is not known how much they may independently cause ASD or trigger inherited genetic vulnerabilities that cause ASD.

After extensive research, medical professionals and researchers have concluded that there is no link between vaccines and autism: it is a genetic cause, with some possible influence from environmental factors during pregnancy. The study that ignited debate by suggesting a link has been retracted, and the original study was proven to be poorly designed with questionable methods.

How early can autism be detected?

Prenatal genetic tests may identify the likelihood of some syndromes related to autism, including Fragile X syndrome. But even if these rare mutations do return a high probability in test results, there is no way to definitively know whether the baby will later show signs of autism.

What is clear is that various distinctive physical behaviors and facial features related to Autism Spectrum Disorder can be noticed at an early age. Social differences may appear earlier or later, and often either cannot be plainly linked to Autism Spectrum Disorder, or may be considered a part of several other genetic or neuro-diverse conditions, such as ADHD or OCD.

What stands out?

When the following behavioral markers appear in a child, it is worth further investigation into a possible autism diagnosis:

Toe walking, difficulty in flexing ankles past 90 degrees

Unusual eating or sleeping patterns

Low or no eye contact

Eye rubbing

Laughing spontaneously when others are not (tonal or musical laugh)

Unusual hand, finger or body movements

Sensitive reactions to sounds, sights, smells, and textures (sticky foods, tags in clothing)

Strong interest in sensory experiences (rubbing a certain texture, licking objects)

Spinning, wobbling, flapping arms, and other repetitive movements

Repetition of words and phrases (echolalia)

Intense interest in lining up or ordering objects

Attachment to rituals and a strong reaction to changes

It is important to bear in mind that many of the historically typical behaviors associated with autism have been found to apply most frequently to male children, leaving many female children undiagnosed.

It should also be noted that while some of these behaviors can cause a disruption in parental expectations, they don’t, for the most part, cause any significant harm to the child. Excessive eye rubbing should be monitored and discouraged if possible as it can cause eye damage. But quirks such as texture enjoyment can simply mean buying or making a new sensory toy.

is autism genetic

Facial features – what does autism look like?

Studies have found that children with autism may present with certain subtle facial features. These may include wide-spaced eyes in an unusually wide upper face. The middle region of the face (nose and cheek area) is shorter. The mouth is wider than usual, and the philtrum (the vertical groove above the top lip) is broader as well.

While these facial features may help alert parents, caregivers, and medical professionals, they don’t drastically differ from children who do not have autism.

So is autism genetic?

The study of autism genetics has advanced in recent decades, setting in motion major changes in how we view autism as a whole. Much remains to be learned and explained in autism susceptibility factors. We already know of many, and there must be many more that we have not yet identified. It would be helpful to be able to pinpoint the genetic variants associated with specific types of autism, but that is not yet possible.

The contribution of genetic inheritance in autism is undeniable. However, without taking a wide array of environmental factors into consideration, we still do not yet have the full picture of what causes autism.

If you notice autistic-like behaviors in your child, first and foremost, speak to your doctor. They will help you understand if your child may need a more in-depth check-up to evaluate for autism and related genetic disorders. Your doctor may also suggest genetic counseling, especially if they also identify other possible symptoms in your child that have no clear cause.

A genetic counselor will be able to understand autism symptoms within the context of a possible rare disease diagnosis, and can recommend best options for further investigation and genetic testing, if relevant.

Understanding exactly where your child’s needs are will help ensure that they are met, and that families and children receive crucial support at the right time.



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