Autism Spectrum Disorder: A Comprehensive Review of Etiology, Diagnosis, Neurobiology, and Emerging Therapeutic Strategies

Autism Spectrum Disorder: A Comprehensive Review of Etiology, Diagnosis, Neurobiology, and Emerging Therapeutic Strategies

Abstract

Autism Spectrum Disorder (ASD) represents a complex neurodevelopmental condition characterized by persistent deficits in social communication and social interaction, alongside restricted, repetitive patterns of behavior, interests, or activities. This review provides a comprehensive overview of ASD, encompassing its evolving diagnostic criteria according to DSM-5, prevalence rates, multifaceted etiology encompassing both genetic and environmental factors, underlying neurobiological mechanisms, common co-occurring conditions, established intervention strategies, available support resources for families, and promising avenues of emerging research. Special emphasis is placed on the intricate interplay between genetic vulnerability and environmental influences in shaping the ASD phenotype, as well as the potential for novel therapeutic interventions targeting specific neurobiological pathways. The report also critically examines the limitations of current diagnostic and therapeutic approaches, advocating for personalized, precision-based strategies informed by advances in genomics, neuroimaging, and behavioral phenotyping. Furthermore, the review highlights the importance of early detection and intervention to optimize developmental outcomes for individuals with ASD.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

1. Introduction

Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental condition marked by significant challenges in social communication, social interaction, and the presence of restricted, repetitive behaviors or interests. The ‘spectrum’ nature of ASD reflects the wide variability in symptom presentation and severity, ranging from individuals with profound cognitive and adaptive impairments to those with average or above-average intelligence who experience primarily social and communication difficulties. The diagnostic criteria for ASD, as defined in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), represents a significant shift from previous iterations, consolidating earlier diagnostic categories such as autistic disorder, Asperger’s syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS) into a single overarching diagnosis. This change reflects the growing recognition that these conditions represent variations along a continuum of the same underlying neurodevelopmental process.

Understanding ASD requires a multifaceted approach, integrating insights from genetics, neurobiology, psychology, and education. While the etiology of ASD remains incompletely understood, a strong genetic component is well established, with estimates suggesting heritability rates as high as 80-90%. However, genetic factors alone are insufficient to explain the rising prevalence rates of ASD, implicating environmental influences as significant contributors to disease risk. Furthermore, ASD is frequently associated with co-occurring medical and psychiatric conditions, such as intellectual disability, epilepsy, anxiety disorders, and attention-deficit/hyperactivity disorder (ADHD), further complicating diagnosis and treatment. The development of effective interventions necessitates a thorough understanding of the individual’s unique symptom profile, cognitive abilities, and co-occurring conditions, as well as the availability of appropriate support resources for families and caregivers.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

2. Diagnostic Criteria and Prevalence

2.1 DSM-5 Diagnostic Criteria

The DSM-5 outlines two core diagnostic domains for ASD: (1) persistent deficits in social communication and social interaction across multiple contexts; and (2) restricted, repetitive patterns of behavior, interests, or activities. To meet the criteria for ASD, individuals must exhibit symptoms in both domains. Within the social communication and social interaction domain, deficits may include: problems with social-emotional reciprocity (e.g., difficulties initiating or responding to social interactions); deficits in nonverbal communicative behaviors used for social interaction (e.g., abnormal eye contact, facial expressions, or body language); and difficulties developing, maintaining, and understanding relationships. The restricted, repetitive behaviors or interests domain encompasses behaviors such as: stereotyped or repetitive motor movements, use of objects, or speech; insistence on sameness, inflexible adherence to routines, or ritualized patterns of verbal or nonverbal behavior; highly restricted, fixated interests that are abnormal in intensity or focus; and hyper- or hyporeactivity to sensory input or unusual interest in sensory aspects of the environment. Furthermore, the DSM-5 specifies severity levels (Level 1, 2, or 3) for both domains, based on the level of support required to function. The shift to a single ASD diagnosis and the inclusion of severity specifiers in the DSM-5 was intended to improve diagnostic reliability and facilitate more tailored treatment planning. However, the changes have also raised concerns about potential impacts on diagnostic rates, access to services, and the identification of individuals with milder forms of ASD.

2.2 Prevalence Rates

The prevalence of ASD has risen dramatically in recent decades. The Centers for Disease Control and Prevention (CDC) estimates that approximately 1 in 36 children in the United States have been identified with ASD, based on data from the Autism and Developmental Disabilities Monitoring (ADDM) Network. This represents a significant increase from previous estimates, which reported prevalence rates of 1 in 150 in 2000 and 1 in 68 in 2014. The reasons for this increase are multifactorial and likely include: (1) broadened diagnostic criteria; (2) increased awareness and improved diagnostic practices; (3) methodological variations across studies; and (4) potentially, a genuine increase in the underlying incidence of ASD. It is important to note that prevalence rates can vary across different geographic regions, demographic groups, and study methodologies. Furthermore, ASD is diagnosed more frequently in males than in females, with a male-to-female ratio of approximately 4:1. This gender difference is not fully understood but may reflect biological differences, diagnostic biases, or both. Emerging research suggests that females with ASD may present with different symptom profiles compared to males, potentially leading to under-diagnosis in females. Understanding the true prevalence of ASD and its underlying causes is critical for planning and allocating resources for diagnosis, treatment, and support services.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

3. Etiology and Risk Factors

3.1 Genetic Factors

A robust body of evidence implicates genetic factors as playing a major role in the etiology of ASD. Twin studies consistently demonstrate significantly higher concordance rates for ASD in monozygotic (identical) twins compared to dizygotic (fraternal) twins, supporting a strong genetic influence. Genome-wide association studies (GWAS) and exome sequencing studies have identified numerous common and rare genetic variants associated with increased ASD risk. Some of the genes most frequently implicated in ASD include those involved in synaptic function, neuronal development, and chromatin remodeling. These genes often converge on common biological pathways, suggesting that disruption of these pathways can contribute to the development of ASD. Furthermore, ASD is associated with a higher incidence of de novo (new) mutations, particularly in genes with roles in neurodevelopment. Copy number variations (CNVs), which are deletions or duplications of large segments of DNA, are also more common in individuals with ASD compared to typically developing individuals. While many different genes and genetic variants have been linked to ASD, each individual variant typically accounts for a small proportion of the overall risk. This suggests that ASD is often a polygenic disorder, resulting from the combined effects of multiple genetic variants, each with a modest effect size. However, in some cases, ASD may be caused by a single, highly penetrant gene mutation, particularly in individuals with syndromic forms of ASD. Identifying specific genetic risk factors for ASD is important for understanding the underlying biological mechanisms and for developing targeted therapies.

3.2 Environmental Factors

Although genetic factors play a significant role in the etiology of ASD, environmental factors are also implicated as contributing to disease risk. Environmental factors encompass a wide range of prenatal, perinatal, and postnatal exposures that may interact with genetic vulnerability to influence neurodevelopment. Prenatal risk factors that have been associated with ASD include: advanced parental age (both maternal and paternal); maternal infections during pregnancy (e.g., rubella, cytomegalovirus); maternal exposure to certain medications (e.g., valproic acid); and maternal metabolic conditions (e.g., diabetes, obesity). Perinatal risk factors include: prematurity; low birth weight; and complications during labor and delivery. Postnatal risk factors that have been investigated include: exposure to environmental toxins (e.g., heavy metals, pesticides); gastrointestinal disorders; and immune system dysregulation. However, it is important to note that the evidence for many of these environmental risk factors is still limited and often inconsistent across studies. Furthermore, it is challenging to disentangle the independent effects of environmental factors from genetic influences, as genes and environment often interact in complex ways. The concept of gene-environment interaction suggests that individuals with certain genetic predispositions may be more susceptible to the adverse effects of specific environmental exposures. Further research is needed to identify specific environmental factors that contribute to ASD risk and to understand how these factors interact with genetic vulnerability to shape the ASD phenotype.

3.3 Gene-Environment Interactions

The etiology of ASD is best understood within a gene-environment interaction framework. This perspective acknowledges that neither genetic predisposition nor environmental exposure alone is sufficient to fully explain the development of ASD in most cases. Instead, ASD likely arises from the complex interplay between genetic vulnerability and environmental influences that shape brain development. This interaction can manifest in several ways. For example, individuals with certain genetic variations may be more sensitive to the effects of specific environmental toxins or stressors, increasing their risk of developing ASD. Conversely, protective environmental factors, such as early intervention or supportive parenting, may mitigate the effects of genetic risk factors and improve developmental outcomes. Epigenetic mechanisms, which involve changes in gene expression without alterations in the underlying DNA sequence, may also play a role in mediating gene-environment interactions in ASD. Environmental exposures can induce epigenetic modifications that alter gene expression patterns, potentially influencing brain development and behavior. Furthermore, the timing of environmental exposures may be critical. The developing brain is particularly vulnerable to environmental insults during sensitive periods of neurodevelopment, when specific brain regions are undergoing rapid growth and differentiation. Understanding the complex interplay between genes and environment is crucial for developing effective strategies for preventing and treating ASD.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

4. Neurobiology of Autism

4.1 Brain Structure and Function

Neuroimaging studies have revealed a range of structural and functional brain abnormalities in individuals with ASD. Structural abnormalities include differences in brain size, gray matter volume, white matter integrity, and cortical thickness. Some studies have reported increased brain volume in early childhood, followed by a period of slower brain growth and potential decline in adolescence. Abnormalities in white matter, which contains the nerve fibers that connect different brain regions, have also been observed, suggesting disruptions in neural connectivity. Functional neuroimaging studies, using techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), have revealed differences in brain activity patterns in individuals with ASD. These studies have consistently reported altered activity in brain regions involved in social cognition, communication, and sensory processing, such as the frontal cortex, temporal cortex, amygdala, and cerebellum. Furthermore, studies have found evidence of altered functional connectivity between different brain regions, suggesting that the brain networks that support social and cognitive functions are disrupted in ASD. A common finding is reduced functional connectivity between frontal regions and posterior regions of the brain. The precise nature and extent of these brain abnormalities can vary across individuals with ASD, reflecting the heterogeneity of the disorder. Future research is needed to understand how these brain abnormalities contribute to the core symptoms of ASD.

4.2 Synaptic Dysfunction

A growing body of evidence suggests that synaptic dysfunction plays a critical role in the pathogenesis of ASD. The synapse is the point of contact between two neurons, where neurotransmitters are released to transmit signals. Synaptic dysfunction can disrupt the flow of information between neurons, leading to impairments in brain function and behavior. Many of the genes implicated in ASD encode proteins that are involved in synaptic development, function, and plasticity. These proteins include: synaptic adhesion molecules (e.g., neuroligins, neurexins), scaffolding proteins (e.g., SHANK3, PSD95), and neurotransmitter receptors (e.g., glutamate receptors, GABA receptors). Mutations in these genes can disrupt synaptic formation, maintenance, or transmission, leading to alterations in synaptic connectivity and function. Animal models of ASD, such as mice carrying mutations in ASD-associated genes, have shown evidence of synaptic abnormalities, including altered synaptic density, morphology, and electrophysiological properties. Furthermore, postmortem studies of brains from individuals with ASD have revealed alterations in synaptic protein expression and synaptic structure. The precise mechanisms by which synaptic dysfunction contributes to the symptoms of ASD are still being investigated, but it is likely that disruptions in synaptic signaling contribute to impairments in social communication, repetitive behaviors, and sensory processing.

4.3 Neurotransmitter Systems

Several neurotransmitter systems have been implicated in the neurobiology of ASD, including the glutamate, GABA, serotonin, and dopamine systems. Glutamate is the primary excitatory neurotransmitter in the brain, and GABA is the primary inhibitory neurotransmitter. An imbalance between excitation and inhibition in the brain is thought to contribute to the development of ASD. Studies have found evidence of altered glutamate and GABA levels in the brains of individuals with ASD, as well as abnormalities in glutamate and GABA receptor function. Serotonin is a neurotransmitter that plays a role in mood, behavior, and social interaction. Abnormalities in the serotonin system have been observed in individuals with ASD, including elevated serotonin levels in blood and altered serotonin receptor function. Selective serotonin reuptake inhibitors (SSRIs), which increase serotonin levels in the brain, are sometimes used to treat anxiety and repetitive behaviors in individuals with ASD. Dopamine is a neurotransmitter that plays a role in motivation, reward, and motor control. Dysregulation of the dopamine system has been implicated in the repetitive behaviors and restricted interests observed in ASD. Further research is needed to understand the precise role of these neurotransmitter systems in the pathogenesis of ASD and to develop targeted therapies that modulate neurotransmitter function.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

5. Co-occurring Conditions

ASD frequently co-occurs with other medical and psychiatric conditions, which can significantly impact the individual’s overall functioning and quality of life. Common co-occurring conditions include: intellectual disability; epilepsy; anxiety disorders; attention-deficit/hyperactivity disorder (ADHD); sleep disorders; gastrointestinal disorders; and sensory processing disorders. Intellectual disability is estimated to affect approximately 30-70% of individuals with ASD. Epilepsy is also more common in individuals with ASD, with prevalence rates ranging from 8-30%. Anxiety disorders, such as social anxiety disorder, generalized anxiety disorder, and obsessive-compulsive disorder, are highly prevalent in individuals with ASD. ADHD is also frequently co-diagnosed with ASD, particularly in individuals with milder forms of ASD. Sleep disorders, such as insomnia, sleep apnea, and restless legs syndrome, are common in individuals with ASD and can exacerbate behavioral and cognitive problems. Gastrointestinal disorders, such as constipation, diarrhea, and abdominal pain, are also more prevalent in individuals with ASD. Sensory processing disorders, which involve difficulties processing and responding to sensory information, are very common in individuals with ASD and can contribute to behavioral problems and social difficulties. The presence of co-occurring conditions can complicate the diagnosis and treatment of ASD. It is important to assess for co-occurring conditions as part of a comprehensive evaluation and to develop treatment plans that address all of the individual’s needs. Ignoring or inadequately addressing co-occurring conditions can limit the effectiveness of interventions for ASD.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

6. Intervention Strategies

6.1 Behavioral Interventions (ABA)

Applied Behavior Analysis (ABA) is a widely used and evidence-based intervention for ASD. ABA is based on the principles of learning and behavior and involves using systematic techniques to teach new skills and reduce challenging behaviors. ABA interventions are typically highly structured and individualized, tailored to the specific needs of the individual with ASD. Common ABA techniques include: discrete trial training (DTT); reinforcement; shaping; prompting; and fading. DTT involves breaking down complex skills into smaller, more manageable steps and teaching each step using repetition and reinforcement. Reinforcement involves providing positive consequences (e.g., praise, rewards) for desired behaviors, which increases the likelihood that the behavior will occur again in the future. Shaping involves reinforcing successive approximations of a target behavior, gradually guiding the individual toward the desired behavior. Prompting involves providing cues or assistance to help the individual perform a desired behavior. Fading involves gradually reducing the level of prompting as the individual becomes more proficient in performing the behavior. ABA interventions can be used to teach a wide range of skills, including: communication skills; social skills; self-help skills; and academic skills. ABA interventions are typically delivered by trained therapists or behavior analysts, often in home, school, or clinic settings. Early intensive behavioral intervention (EIBI), which involves providing ABA therapy for 20-40 hours per week, has been shown to be effective in improving developmental outcomes for young children with ASD. However, ABA is not a one-size-fits-all approach, and the specific techniques and strategies used should be tailored to the individual’s needs and preferences. Criticisms of ABA sometimes involve it being overly prescriptive and not always generalized outside of the test environment. Modern ABA increasingly takes a more holistic approach to therapy.

6.2 Speech and Language Therapy

Speech and language therapy is an important intervention for individuals with ASD, as communication difficulties are a core feature of the disorder. Speech and language therapists work with individuals with ASD to improve their communication skills, including: receptive language (understanding language); expressive language (using language); and social communication skills. Speech and language therapy interventions may involve: teaching new vocabulary; improving grammar; practicing conversational skills; and using augmentative and alternative communication (AAC) systems. AAC systems, such as picture exchange communication system (PECS) and speech-generating devices, can be used to help individuals with ASD who have limited or no verbal communication skills. Speech and language therapists also work with individuals with ASD to improve their social communication skills, such as: understanding social cues; initiating and maintaining conversations; and responding appropriately to others. Furthermore, speech and language therapy can address other communication related challenges such as articulation and swallowing difficulties.

6.3 Occupational Therapy

Occupational therapy (OT) is another important intervention for individuals with ASD. Occupational therapists work with individuals with ASD to improve their daily living skills, sensory processing abilities, and motor skills. OT interventions may involve: teaching self-care skills (e.g., dressing, bathing, eating); improving fine motor skills (e.g., writing, buttoning); improving gross motor skills (e.g., running, jumping); and addressing sensory processing difficulties. Many individuals with ASD have sensory sensitivities, which can lead to behavioral problems and difficulties with daily activities. Occupational therapists can use sensory integration therapy to help individuals with ASD regulate their sensory input and reduce sensory-related anxiety. Occupational therapists also work with individuals with ASD to improve their motor skills, which can impact their ability to perform daily tasks and participate in social activities.

6.4 Social Skills Training

Social skills training is an intervention designed to improve the social competence of individuals with ASD. Social skills training interventions typically involve teaching specific social skills, such as: initiating conversations; maintaining conversations; understanding social cues; and responding appropriately to social situations. Social skills training interventions may be delivered in individual or group settings. Group-based social skills training can provide opportunities for individuals with ASD to practice social skills with their peers. Social skills training interventions often incorporate role-playing, modeling, and feedback to help individuals with ASD learn and practice social skills. Some social skills training programs also use video modeling, which involves watching videos of individuals demonstrating appropriate social behaviors. Social skills training interventions can be effective in improving the social functioning of individuals with ASD, but it is important to note that social skills are complex and require ongoing practice and support.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

7. Support Resources for Families

Families of individuals with ASD often require significant support and resources to navigate the challenges of raising a child with a developmental disability. Support resources for families may include: parent training programs; support groups; respite care; financial assistance; and legal advocacy. Parent training programs provide parents with information and skills to help them manage their child’s behavior and promote their development. Support groups provide a forum for parents to connect with other families who have children with ASD, share experiences, and receive emotional support. Respite care provides temporary relief for caregivers, allowing them to take a break from the demands of caring for a child with ASD. Financial assistance may be available to help families cover the costs of medical care, therapy, and other services. Legal advocacy can help families navigate the special education system and ensure that their child receives appropriate educational services. Numerous organizations provide support resources for families of individuals with ASD, including: Autism Speaks; the Autism Society of America; and the National Autism Center. Access to these support resources can significantly improve the well-being of families and enhance the outcomes for individuals with ASD.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

8. Emerging Research

8.1 Biomarkers

Emerging research is focused on identifying biomarkers for ASD, which could help improve diagnosis, treatment, and prevention efforts. Biomarkers are measurable indicators of a biological state or condition. Potential biomarkers for ASD include: genetic markers; neuroimaging markers; electrophysiological markers; and biochemical markers. Genetic markers, such as specific gene mutations or copy number variations, could be used to identify individuals at increased risk for ASD. Neuroimaging markers, such as differences in brain structure or function, could be used to track the progression of ASD and to assess the effectiveness of interventions. Electrophysiological markers, such as differences in EEG patterns, could be used to identify subtypes of ASD and to predict treatment response. Biochemical markers, such as differences in neurotransmitter levels or immune system function, could provide insights into the underlying biological mechanisms of ASD. Identifying reliable and valid biomarkers for ASD is a major challenge, but it has the potential to revolutionize the field.

8.2 Genetic Studies

Genetic studies continue to play a crucial role in understanding the etiology of ASD. Genome-wide association studies (GWAS) and exome sequencing studies are being used to identify new genes and genetic variants associated with ASD. These studies are becoming increasingly sophisticated, incorporating larger sample sizes and advanced analytical techniques. Furthermore, researchers are investigating the role of epigenetic modifications in ASD. Epigenetic modifications, such as DNA methylation and histone acetylation, can alter gene expression without changing the underlying DNA sequence. These modifications can be influenced by environmental factors and may play a role in mediating gene-environment interactions in ASD. Understanding the genetic architecture of ASD is essential for developing targeted therapies and for providing genetic counseling to families.

8.3 Precision Medicine

A growing trend in ASD research is the development of precision medicine approaches. Precision medicine involves tailoring treatment to the individual based on their unique genetic, biological, and behavioral characteristics. This approach recognizes that ASD is a heterogeneous disorder and that individuals may respond differently to different treatments. Precision medicine approaches may involve: using genetic testing to identify individuals who are likely to respond to specific medications; using neuroimaging to identify individuals who are likely to benefit from specific behavioral interventions; and using biomarkers to monitor treatment response. The goal of precision medicine is to optimize treatment outcomes by matching individuals with the most appropriate interventions. However, precision medicine approaches are still in their early stages of development, and further research is needed to validate their effectiveness.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

9. Conclusion

Autism Spectrum Disorder (ASD) is a complex and heterogeneous neurodevelopmental condition with a significant impact on individuals, families, and society. While substantial progress has been made in understanding the etiology, diagnosis, and treatment of ASD, many challenges remain. Future research efforts should focus on: identifying reliable biomarkers for ASD; elucidating the complex interplay between genetic and environmental factors; developing precision medicine approaches to tailor treatment to the individual; and improving access to evidence-based interventions and support resources for families. Furthermore, it is essential to promote greater awareness and understanding of ASD in the general population and to reduce the stigma associated with this condition. By working together, researchers, clinicians, educators, and families can improve the lives of individuals with ASD and create a more inclusive and supportive society.

Many thanks to our sponsor Esdebe who helped us prepare this research report.

References

• American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).
• Baio, J., Wiggins, L. D., Christensen, D. L., Maenner, M. J., Daniels, J., Warren, Z., … & Dowling, N. F. (2018). Prevalence of autism spectrum disorder among children aged 8 years—Autism and developmental disabilities monitoring network, 11 sites, United States, 2014. MMWR. Surveillance Summaries, 67(6), 1-23.
• Lord, C., Brugha, T. S., Charman, T., Cusack, J., Dumas, G., Emerson, J., … & Baird, G. (2022). Autism spectrum disorder. Nature Reviews Disease Primers, 6(1), 1-27.
• Geschwind, D. H., & State, M. W. (2015). Autism spectrum disorders. Annual Review of Neuroscience, 38, 373-398.
• Rylaarsdam, L., & Guemsey, G. F. (2008). Epidemiology of autism spectrum disorders. CNS spectrums, 13(4), 346-356.
• Sandin, S., Lichtenstein, P., Kuja-Halkola, R., Hultman, C. M., Reichenberg, A., & Boman, M. (2014). The familial risk of autism. JAMA, 311(17), 1770-1777.
• Tick, B., Bolton, P., Happé, F., Rutter, M., & Rijsdijk, F. (2016). Heritability of autism spectrum disorders: a meta-analysis of twin studies. Journal of Child Psychology and Psychiatry, 57(5), 585-595.
• Lord, C., Elsabbagh, M., Baird, G., & Veenstra-VanderWeele, J. (2018). Autism spectrum disorder. The Lancet, 392(10145), 508-520.
• Courchesne, E., Campbell, K., & Solso, S. (2011). Brain growth across the life span in autism: age-specific changes in anatomical pathology. Brain research, 1380, 138-149.
• Ecker, C., Rocha-Rego, V., Marquand, A. F., Mourao-Miranda, J., Johnston, P., Daly, E., … & Murphy, D. G. (2015). Widespread structural brain differences in children and adolescents with autism spectrum disorder. Cerebral cortex, 25(10), 3583-3595.
• Müller, R. A., Shih, P., Keehn, B., Deyoe, J. R., Leyden, K. M., & Head, T. L. (2011). Underconnectivity in autism: a meta-analysis and systematic review. Brain, 134(3), 783-792.
• Bourgeron, T. (2015). From monogenic diseases to autism spectrum disorders: toward a genetic architecture of autism. Human molecular genetics, 24(R1), R1-R9.
• Südhof, T. C. (2008). Neuroligins and neurexins link synaptic function to autism. Neuron, 60(6), 923-931.
• Dumas, G., & Bourgeron, T. (2013). The genetics of autism spectrum disorders. Human Genetics, 131(5), 671-694.
• Rogers, S. J., Vismara, L., & Wagner, A. L. (2023). Evidence-Based Comprehensive Interventions for Toddlers and Preschoolers with Autism. Journal of Autism and Developmental Disorders, 1-20.
• Ozonoff, S., Goodlin-Jones, B. L., & Solomon, M. (2005). Evidence-based assessment of autism spectrum disorders in children and adolescents. Journal of Clinical Child & Adolescent Psychology, 34(3), 523-540.