Is Autism Hereditary?

Research shows that genetics play a major part in autism, but there is no single “autism gene.” Instead, hundreds of different genetic variations can interact to increase the likelihood of an autism diagnosis. Autism is not caused by parenting style or emotional upbringing. Many children with autism are born to parents with no history of the condition in their families. 

Research shows that genetics play a major role in autism. Studies of twins and families estimate that autism is highly heritable, meaning inherited genetic factors significantly influence the likelihood of developing it.

Autism is considered to be one of the most heritable conditions with an estimate that genetics account for roughly 60% to 90% of the risk for developing autism.

Inherited Trait: A child may inherit specific genetic combinations from one or both parents and the parents may carry the gene without having autism themselves. They pass down a unique combination down to their child or they may exhibit mild, sub-clinical traits (known as the Broader Autistic Phenotype). 

Spontaneous Mutations: A significant portion of autism cases are caused by de novo mutations. These are brand-new, uninherited genetic changes that occur spontaneously during early fetal development, even if neither parent carries them.

Multiple Genes: Autism rarely comes from a single gene mutation. It is usually a complex condition involving hundreds of different genetic variations working together. 

The gene that carries autism can be found in people that don’t have autism. Not everyone that is exposed to an environmental risk factor for autism will develop the disorder. In fact, most will not. If one child in a family is autistic, the chances are higher that a sibling may also be autistic compared with the general population.

That said, genetics are not the whole story. Alongside genetics, certain environmental factors during pregnancy or early development can contribute to the likelihood of a child developing autism Environmental and developmental factors during pregnancy and early brain development may also contribute.  

• Advanced Parental Age.

• Certain Pregnancy Complications.

• Premature Birth.

  
  

Twin Studies: If one identical twin is autistic, the likelihood that the other twin will also be autistic is between 60% and 90%.

Siblings: Having one child on the spectrum increases the chances of having another autistic child compared to the general population. Because the trait is polygenic and never guaranteed, neurotypical parents can have an autistic child, just as autistic parents can have neurotypical (non-autistic) children.