Is ASD Genetic or Environmental?
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About Autism Spectrum Disorder
Autism spectrum disorder (ASD) is a condition that affects how the brain develops and functions. It can influence how a person communicates and interacts with others. People with autism may also have restricted interests and engage in repetitive behaviors.1
These characteristics are required for an autism diagnosis, but they are not the same for every individual. That’s why it’s called a spectrum.1
People with ASD can show a wide range of signs and symptoms. For example, some individuals are nonverbal, while others have advanced conversational skills. Some need significant support with daily activities, while others live independently with little to no support.1
Signs and Symptoms
Signs and symptoms of ASD can vary significantly. Some may appear early in childhood, such as avoiding eye contact or showing little interest in caregivers. Others may become more noticeable later in life.1
Signs and symptoms of ASD may include:1
· Problems with social communication and interaction. Examples: not responding to their name, avoiding physical contact, poor eye contact, delayed speech or not speaking, speaking with an unusual tone or rhythm, repeating words or phrases, difficulty understanding questions or directions, not showing emotions, passive or aggressive behaviors, and difficulty interpreting social cues.
· Limited, repetitive patterns of behavior, interests, or activities. Examples: repetitive movements such as rocking, spinning, or hand-flapping; strict adherence to routines or rituals; clumsiness; exaggerated body movements; sensitivity to light, sound, or touch; intense focus on a specific object or activity; and strong preferences for certain foods.
Is autism genetic?
The causes of autism are complex and not fully understood. Current research indicates that a combination of genetic and environmental factors is involved.2
Genetic factors
Studies suggest that families with one autistic child are up to 25 times more likely to have another child with autism compared to the general population. Moreover, studies of twins show that if one identical twin has autism, there’s a high chance (about 60 to 90%) that the other twin will also have it. For non-identical twins, that chance is lower, ranging from 0 to 24%.2
Various candidate genes and chromosomal alterations have been associated with ASD. In some individuals, ASD occurs as part of an underlying genetic condition, such as Rett syndrome or fragile X syndrome.2
Certain genetic mutations may also increase the risk of ASD by affecting how the brain develops or how brain cells communicate.2
Environmental factors
Researchers are exploring whether factors such as advanced parental age, environmental exposures (like pollution), certain medications, or complications during pregnancy may increase the risk of developing autism. Importantly, there is no evidence linking vaccines to an increased risk of ASD.2
Diagnosis
There’s no specific medical test to diagnose ASD. Specialists look at the patient’s development and behavior to identify signs and symptoms of the condition. According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), a person must have persistent déficits in social communication and interaction, along with restricted and repetitive behaviors, to meet the diagnostic criteria for ASD.3
Management and treatment
Although there is no cure for ASD, its symptoms can be effectively managed with appropriate treatment. Treatment for ASD focuses on reducing symptoms that interfere with daily functioning and quality of life. Because ASD affects each person differently, treatment plans are tailored to the individual.3
Treatment for ASD usually involves a multidisciplinary approach that may include speech and language therapy, occupational therapy, physical therapy, cognitive-behavioral therapy, participation in social skills groups, and sometimes, medications to manage symptoms like anxiety, inability to focus, or high energy levels.3
Key takeaways
The exact cause of ASD is still not fully understood. Evidence indicates a combination of genetic and environmental factors. Diagnosis involves assessing a person’s behavior and development to identify key signs and symptoms. While there is no cure, appropriate support and treatment can help manage symptoms and improve daily functioning and quality of life.
References
1- Hodges H, Fealko C, Soares N. Autism spectrum disorder: definition, epidemiology, causes, and clinical evaluation. Translational pediatrics. 2020 Feb;9(Suppl 1):S55. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7082249/
2- Almandil NB, Alkuroud DN, AbdulAzeez S, AlSulaiman A, Elaissari A, Borgio JF. Environmental and genetic factors in autism spectrum disorders: special emphasis on data from Arabian studies. International journal of environmental research and public health. 2019 Feb;16(4):658. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6406800/
3- CDC. About Autism Spectrum Disorder. Available at: https://www.cdc.gov/autism/about/index.html