Autism Spectrum Disorder

Understanding the condition

From: MedlinePlus, National Library of Medicine

Autism spectrum disorder (ASD) is a neurological and developmental disorder that begins early in childhood and lasts throughout a person's life. It affects how a person acts and interacts with others, communicates, and learns. It includes what used to be known as Asperger syndrome and pervasive developmental disorders.

It is called a "spectrum" disorder because people with ASD can have a range of symptoms. People with ASD might have problems talking with you, or they might not look you in the eye when you talk to them. They may also have restricted interests and repetitive behaviors. They may spend a lot of time putting things in order, or they may say the same sentence again and again. They may often seem to be in their "own world."

At well-child checkups, the health care provider should check your child's development. If there are signs of ASD, your child will have a comprehensive evaluation. It may include a team of specialists, doing various tests and evaluations to make a diagnosis.

The causes of ASD are not known. Research suggests that both genes and environment play important roles.

There is currently no one standard treatment for ASD. There are many ways to increase your child's ability to grow and learn new skills. Starting them early can lead to better results. Treatments include behavior and communication therapies, skills training, and medicines to control symptoms.

Genetic causes described in the linked summary

From: MedlinePlus Genetics

Changes in over 1,000 genes have been reported to be associated with ASD, but a large number of these associations have not been confirmed. Many common gene variations are thought to affect the risk of developing ASD, but not all people with one or more of these gene variations will be affected. Individually, most of the gene variations have only a small effect. Genetic factors are estimated to contribute 40 to 80 percent of ASD risk.

The risk from gene variants combined with environmental risk factors, such as parental age, birth complications, and others that have not been identified, determine an individual's risk of developing this complex condition.

By contrast, in about 2 to 4 percent of people with ASD, rare gene mutations or chromosome abnormalities are thought to be the cause of the condition, often as a feature of syndromes that also involve additional signs and symptoms affecting various parts of the body. For example, mutations in the ADNP gene cause a disorder called ADNP syndrome. In addition to ASD and intellectual disability, this condition involves distinctive facial features and a wide variety of other signs and symptoms. Some of the other genes in which rare mutations are associated with ASD, often with other signs and symptoms, are ARID1B, ASH1L, CHD2, CHD8, DYRK1A, POGZ, SHANK3, and SYNGAP1. In most individuals with ASD caused by rare gene mutations, the mutations occur in only a single gene.

Many of the genes associated with ASD are involved in the development of the brain. The proteins produced from these genes affect multiple aspects of brain development, including production, growth, and organization of nerve cells (neurons). Some affect the number of neurons that are produced, while others are involved in the development or function of the connections between neurons (synapses) where cell-to-cell communication takes place, or of the cell projections (dendrites) that carry signals received at the synapses to the neuron. Many other genes associated with ASD affect development by controlling (regulating) the activity of other genes or proteins.

The specific ways that changes in these and other genes relate to the development of ASD are unknown. However, studies indicate that during brain development, some people with ASD have more neurons than normal and overgrowth in parts of the outer surface of the brain (the cortex). In addition, there are often patchy areas where the normal structure of the cortex is disturbed. Normally the cortex has six layers, which are established during development before birth, and each layer has specialized neurons and different patterns of neural connection. The neuron and brain abnormalities occur in the frontal and temporal lobes of the cortex, which are involved in emotions, social behavior, and language. These abnormalities are thought to underlie the differences in socialization, communication, and cognitive functioning characteristic of ASD.

Inheritance described in the linked summary

From: MedlinePlus Genetics

ASD has a tendency to run in families, but the inheritance pattern is usually unknown. People with gene changes associated with ASD generally inherit an increased risk of developing the condition, rather than the condition itself. When ASD is a feature of another genetic syndrome, it can be passed on according to the inheritance pattern of that syndrome.

Which doctor should you see?

The suggested department for discussing Autism Spectrum Disorder is Paediatrics, with a paediatrician as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics; Developmental Paediatrics; Psychiatry for adults where appropriate.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• How do the findings compare with the child’s growth and development over time?
• Which changes should caregivers record between appointments?
• Are school, developmental or paediatric specialist services relevant?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.