How Does a Child Actually Get Autism?

Autism

Explore 'how does a child get autism?' Discover genetic and environmental factors, early signs, and impacts.

Steven Zauderer

November 4, 2024

9 min read

min read

Understanding Autism Risk Factors

In the quest to understand "how does a child get autism", researchers have identified several risk factors that contribute to the development of autism and autism spectrum disorders (ASD). It is important to note that these factors do not guarantee that a child will develop autism, but they do increase the likelihood. These risk factors fall into two main categories: parental characteristics and obstetric conditions.

Parental Characteristics

Parental characteristics that have been identified as potential autism risk factors include maternal and paternal age, maternal place of birth, and maternal mental health conditions.

According to a study cited by JAMA Pediatrics, both advanced maternal and paternal age are associated with an increased risk of autism in children. In fact, the risk of autism increases by 29% for every 10-year elevation in fathers' age [1].

Another significant parental factor is the mother's place of birth. Mothers born outside of Europe or North America have been found to have a higher risk of having a child with autism JAMA Pediatrics.

Furthermore, maternal mental health conditions such as depression, anxiety, and personality disorders are associated with an increased risk of autism in children.

Obstetric Conditions

Obstetric conditions, those related to pregnancy and childbirth, have also been identified as potential risk factors for autism. According to an NCBI meta-analysis, maternal prenatal medication use, bleeding, gestational diabetes, and being first born versus third or later, are associated with an increased risk of autism.

Additionally, birth weight, duration of gestation, and intrapartum hypoxia (a condition where the fetus doesn't receive enough oxygen during childbirth) have also been significantly associated with autism JAMA Pediatrics.

Maternal viral infections in the first trimester of pregnancy, such as rubella, measles, mumps, chickenpox, influenza, herpes, and cytomegalovirus, also increase the risk of autism in the fetus.

It is important to note that many of these risk factors are interrelated and their effects can be cumulative. Therefore, it's crucial to consider the entire range of autism risk factors when trying to understand the causes of autism. This understanding can guide future research and help inform prevention strategies.

Genetic and Environmental Factors

Examining the origins of autism, it becomes clear that the condition is influenced by a combination of genetic and environmental factors. These factors intertwine in complex ways to influence the development of autism in a child.

Genetic Contributions to Autism

The role of genetics in autism development is significant. Heritability estimates suggest that shared genes, rather than shared environment, contribute to autism risk [2]. However, it's important to understand that there isn't a single "autism gene" that determines whether a child will develop the condition.

Instead, research points to a huge genetic heterogeneity in autism. This means that multiple genetic alterations can influence the risk of autism, affecting limited biological pathways of brain development and plasticity [2].

In addition to these genetic influences, certain parental characteristics have also been associated with an increased risk of autism and autism spectrum disorders. These include advanced maternal age, advanced paternal age, and maternal place of birth outside Europe or North America [3].

Environmental Influences on Autism

While genetics play a crucial role in autism development, environmental factors are also significant contributors. The meta-analysis results indicate that environmental factors such as maternal prenatal medication use, bleeding, gestational diabetes, being first born vs. third or later, and having a mother born abroad are associated with autism risk [4].

Moreover, environmental factors have been shown to contribute significantly to autism risk, reinforcing the need for further research in this area [2]. These could include factors related to pregnancy and birth complications, exposure to toxins, and other factors that affect a child's early development.

In conclusion, while it's clear that both genetic and environmental factors contribute to the development of autism, the complex interplay between these factors makes it difficult to predict with certainty how a child gets autism. Understanding these factors can, however, help in early detection and intervention, potentially improving outcomes for children with autism.

Prevalence and Onset of Autism

Understanding the prevalence and onset of autism is key to demystifying the question, "how does a child get autism?"

Prevalence Rates

The prevalence of autism has significantly increased over the past few decades. In the 1980s, the prevalence rate was approximately 4-5 cases per 10,000 children, which increased to 30-60 cases in the 1990s. In 2012, the Autism and Developmental Disabilities Monitoring Network published a combined autism spectrum disorder (ASD) prevalence of 11.3 per 1000 children aged 8 years, equating to one in eighty-eight children [1].

More recent estimates from the Centers for Disease Control and Prevention (CDC) indicate that about 1 in every 54 children in the U.S. has been identified with ASD, illustrating that the prevalence rates continue to rise. Additionally, the CDC indicates that ASD is four times more common among boys than girls.

Year	Prevalence per 10,000 children
1980s	4-5
1990s	30-60
2012	113

Age of Onset

In terms of autism onset, the symptoms of ASD can be identified in children as early as 18 months of age. However, the actual age of diagnosis often occurs later, typically around the age of 4 years. Early detection and intervention are crucial in improving the outcomes for children with autism.

It's important to note that the journey to understanding autism is ongoing. Researchers continue to explore the various genetic, environmental, and developmental factors that contribute to its onset and progression. As scientific knowledge expands, so does the potential to improve the lives of those living with autism.

Early Signs and Symptoms

As we delve into understanding how a child gets autism, it’s crucial to identify the early signs and symptoms associated with Autism Spectrum Disorder (ASD). These can be categorized into behavioral indicators and communication challenges.

Behavioral Indicators

Children with ASD commonly exhibit certain behavioral patterns that serve as indicators of the disorder. These include challenges in social communication and interaction, as well as restricted or repetitive behaviors or interests [6]. Many children display these symptoms by 12 to 18 months of age or earlier, as these behavioral signs often emerge early in development.

The behavioral indicators can be broken down as follows:

Social Interaction Challenges: Difficulties understanding social cues, showing empathy, and engaging in social interactions.
Restricted Behaviors: Frequent engagement in repetitive behaviors or showing an intense interest in specific subjects.
Repetitive Behaviors: Repeating specific behaviors or having unusual behaviors.

Communication Challenges

Communication challenges are another major symptom of ASD. Children with ASD may have difficulty developing language skills, understanding what others say to them, and communicating nonverbally through hand gestures, eye contact, and facial expressions [5]. Some children may not be able to communicate using speech or language, while others may have limited speaking skills or rich vocabularies about specific subjects. Difficulties with understanding body language and vocal tones also affect their ability to interact with others.

The communication challenges can be summarized as follows:

Language Development: Trouble developing language skills and understanding what others say.
Nonverbal Communication: Difficulty communicating nonverbally, such as through hand gestures, eye contact, and facial expressions.
Speech and Vocabulary: Some children may not be able to communicate using speech, while others may have rich vocabularies in specific areas.

It's important to note that these signs and symptoms can vary greatly from one child to another. Therefore, if a parent or caregiver notices any of these signs in their child, they should seek professional help for a comprehensive evaluation. Early detection and intervention can significantly improve the child's development and quality of life.

Impact on Brain Structure

The brain structure of individuals with autism shows certain distinctive characteristics. Research has highlighted changes in the brain development process, as well as key structural differences when compared to non-autistic individuals. Both of these aspects contribute to our understanding of how a child might acquire autism.

Brain Development in Autism

One of the profound differences in individuals with autism is seen in the pace of brain development. Infants who are later diagnosed with autism often exhibit unusually fast growth in certain brain regions. For instance, autistic children typically demonstrate significantly faster expansion of the surface area of their cortex between the ages of 6 and 12 months. Additionally, the brain volume increases much faster in autistic children in their second year of life compared to their non-autistic peers.

Another noteworthy observation is the presence of excess cerebrospinal fluid in some children who are later diagnosed with autism. This excess fluid tends to be present from as early as 6 months of age and can persist through age 39. The surplus fluid may contribute to having an enlarged head, and those with the most fluid tend to exhibit the most prominent autism traits later in life.

Structural Differences

In addition to differences in the rate of brain development, there are also several structural differences in the brains of individuals with autism. For instance, autistic people often have an enlarged hippocampus. They also typically exhibit decreased amounts of brain tissue in parts of the cerebellum and alterations in white matter, which connects different brain regions [7].

Furthermore, preschoolers with autism demonstrate significant differences in the structure of multiple white-matter tracts. Autistic toddlers and adolescents also exhibit alterations in white matter throughout the brain, as shown in a 2020 study.

Interestingly, these white-matter changes in preschoolers with autism differ by sex. Autistic girls tend to show increased structural integrity in the corpus callosum compared with non-autistic girls. This measure is lower in autistic boys compared to non-autistic boys. However, other structural differences, such as the rate of brain growth and the amount of cerebrospinal fluid, appear similar between the sexes.

These findings highlight the complex interplay of factors that contribute to the onset of autism. Further research is needed to deepen our understanding of these brain structure changes and their implications for the diagnosis and treatment of autism.

Social Challenges and Support

Children with autism may face a range of challenges, particularly in social interactions and mental health. Understanding these challenges can help in providing necessary support and intervention.

Social Interaction Difficulties

Children with autism often struggle with social interactions. These challenges might manifest as difficulties in communication skills, both verbal and nonverbal, understanding of social cues, and repetitive and restricted behaviors. Lack of empathy is also commonly observed in these individuals.

In addition, these social interaction difficulties make children with autism more susceptible to bullying. The impact of such bullying can be severe, leading to increased anxiety, depression, low self-esteem, and academic difficulties.

Social Interaction Challenges	Impact
Communication difficulties	Misunderstanding; frustration
Lack of understanding of social cues	Social isolation; bullying
Repetitive and restricted behaviors	Stigmatization; bullying
Lack of empathy	Difficulty in building relationships

Mental Health Implications

These struggles with social interaction contribute to mental health issues in children with autism. Increased stress, anxiety, and depression are often seen in these individuals, and proper support and intervention are essential to address these concerns and promote overall well-being.

Abnormal neural connectivity is also observed in individuals with autism, which may contribute to difficulties in executive function, complex information processing, theory of mind, and empathy. The cerebellum, one of the most common sites of anatomic abnormality in autism, is implicated in deficits of long-range connectivity and coordination of cognitive functions.

A comprehensive understanding of these challenges is crucial for providing necessary support and interventions for children with autism. Providing a supportive and understanding environment, both at home and school, can help these children navigate their social and mental health challenges effectively.