Is autism genetic?

April 22, 2022

According to research, autism in some children is inherited or developed through genes. If a parent carries even a single Autism Spectrum Disorder (ASD) gene, having a child with autism increases. However, genetics may not be the sole cause of autism. Different environmental factors may also be responsible for developing autism.

According to the latest Health Day news report, 80% of the risk of a child developing autism is due to inherited genes, while only 20% is based on environmental factors. Furthermore, the Centers for Disease Control and Prevention states that autism is due to genetic factors. Currently, the prevalence rate is 1:44 children in the United States.

Does an autism gene exist?

Experts say that autism can be inherited through more than a hundred genes. However, experts also claim that there are no specific genes encoded for ASD. Most of these genetic sequences are considered very important to undergo the association between neurons or control the remaining genes' expressions. Meaning that autism is not associated with mutations in a single genetic sequence. It is hypothesized that thousands of genetic mutations may contribute to a child developing autism. Hence, no specific mutation or change in the DNA sequence can be termed "an autism gene." Furthermore, not every child carries the same mutated gene(s) that causes autism.

How are genes responsible for autism?

When there are changes or mutations in the DNA – away from the standard genetic sequence – chances of developing autism in a child increases. Sometimes, these mutations affect only a single DNA base pair (mutations in one gene); however, these genetic variants are present in thousands of people.

Some gene variants from children with autism are very rare, found in less than one percent of the world's population. Such rare variants are not subtle and may even cause more severe effects and manifest as stronger deficits.

Usually, mutations that are associated with autism are considered to be rare. Hence, it is challenging to determine if your child's autism is genetic or not. It is significantly even more complicated to find common variants associated with autism. Due to these challenges, experts are still studying these genetic factors and identifying new gene variants linked to autism.

Does autism continue to be inherited in the family?

According to CDC research, autism can continue to be inherited in a family. Some genes change during the pregnancy period and can increase the child's risk of developing autism. Experts also state that children who have siblings with autism may have a higher chance of developing it. 

The child can inherit one or more of these altered genes from a parent even if the parent does not display signs or symptoms of autism. Such genetic changes occur during different stages of the child's development process. When there is one child with autism in the family, there is approximately a one-in-five chance of siblings showing similar symptoms of autism.

How do people acquire genetic mutations?

Mutations can be, but are not always inherited from the child's parents. These mutations are developed in the child during the fertilization process. By comparing the DNA sequence of different people, these mutations can be identified as rare or common. The conditions and possibility of developing autism in a child increase as the mutations develop.

Is autism developed through maternal or paternal lineage? 

Autism can be caused due to defects in the cells or mutations. It also equally depends on the different autism-causing genes that may or may not be inherited by the parents. In most mutation cases, it is not explicitly inherited from either the mother's side or the father's side. 

On the other hand, the genetic variants in the child's DNA can be inherited from any parent or both. It may come either from the Y chromosome or the X chromosome. However, research states that, in most cases, it comes from the male chromosome (Y). According to research, changes in genetic variants that control gene functioning also play a crucial role in developing autism. Most of these changes were found in the child's father, who was not affected by autism, which means these genes can be either recessive or dominant.

Risk of autism among siblings

Experts have developed genetic tests to determine whether autistic genetic variants are passed on to the child from their parents. The inheritance of these genetic variants can be considered as "genetic imprinting." In this process, the functioning of the genes is stopped for some time during the fertilization process.

Studies show that the risk in the second-born child is lower if the first affected child is a girl. The risk depends on the genetic make-up found in the first affected child. Therefore, if one child has autism in a family, other children should be monitored as the chances of developing autism is increased.

Can genetic mutations be tested before the child's birth?

Various tests can help determine the genetic variations that may contribute to autism development. Genetic testing can be done before the child's birth by monitoring the chromosomes and identifying any abnormalities. These tests cannot guarantee if the child will be diagnosed with autism after birth. If the child shows any symptoms after birth, the child can be assessed and diagnosed later.

Can we rely on genetic tests?

It is not possible to test hundreds of genes to identify whether your child is associated with autism or not. Children with autism have different characteristics, and there are no two children with autism who can be considered the same. However, the tests can help identify any related concerns. When these traces are found in a single child or parent, it further helps to identify or diagnose the possibility of autism in siblings.

Therapies that help children with autism

  • Behavior and Communication Therapies: Teaching children how to communicate, engage in different social situations, and learn daily living skills through ABA therapy.
  • Family Therapies: Parents and other family members can learn how to play and interact with children with autism to improve their social interaction skills, daily living skills, and communication.
  • Other Therapies: Other autism therapies include educational therapies to address challenges, etc.

Conclusion

Autism can occur due to genetic as well as other environmental factors. Many types of research and tests are taking place for further progress in autism care and therapies. No matter the cause, as a parent, it is better to take proper care and treat your child with the necessary therapies. 

At Songbird, our highly-qualified therapists help children with autism overcome their challenges. We’re building a world where every child can access world-class care at home, uniquely tailored to them.

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