Rare Pulmonology News

Disease Profile

Autism spectrum disorder

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)



Behavioral and mental disorders


Autism spectrum disorder (ASD) is a condition that affects the development of social and communication skills. It includes features of four conditions which were once thought to be separate syndromes autistic disorder, Asperger syndrome, childhood disintegrative disorder, and pervasive developmental disorder. Signs and symptoms often become apparent in the first 2-3 years of life and vary significantly from person to person. Common symptoms shared by people with ASD include restrictive and repetitive behaviors, social impairment and communication difficulties. The underlying cause of ASD is generally unknown and it is likely that a variety of factors contribute to the development of the condition. ASD appears to run in some families, suggesting that genetics may play a role in some cases. Although there is no cure for ASD, treatment is available that significantly improves the long-term outlook for affected people. Treatment often includes a combination of techniques such as medications, occupational therapy, speech therapy and physical therapy.[1][2][3]


The signs and symptoms of autism spectrum disorder generally become apparent in the first two to three years of life and vary significantly from person to person. In general, common features shared by people with ASD include restrictive and repetitive behaviors, social impairment and communication difficulties.[3]

Restrictive and repetitive behaviors:[2][3][1][4]

  • Sensitivity to changes in routine
  • Repetitive body movements
  • Overly focused interests, such as with moving objects or parts of objects
  • Lasting, intense interests in certain topics, such as numbers, details, or facts.

Social impairment:[2][3][1][4]

  • Difficulty making friends
  • Unable to play interactive games
  • No response to eye contact or smiles, or may avoid eye contact
  • Prefers to be alone rather than with others
  • Unable to show empathy

Communication difficulties:[2][3][1][4]

  • Develops language slowly or not at all
  • Trouble starting and maintaining a conversation
  • Uses gestures instead of words
  • Speaks at length about a favorite subject without noticing that others are not interested or without giving others a chance to respond
  • Uses words that seem odd, out of place, or have a special meaning known only to those familiar with that person's way of communicating
  • Facial expressions, movements, and gestures may not match what is being said
  • Unusual tone of voice that may sound sing-song or flat and robot-like
  • Doesn't point to show other people objects (normally occurs in the first 14 months of life)
  • Repeats words or memorized passages, such as commercials

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
30%-79% of people have these symptoms
EEG abnormality
Increased serum serotonin
Percent of people who have these symptoms is not available through HPO
Childhood onset
Symptoms begin in childhood
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

Impaired ability to form peer relationships
Impaired use of nonverbal behaviors
Impaired use of nonverbal behaviours
Inflexible adherence to routines or rituals
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Lack of spontaneous play
Multifactorial inheritance
Restrictive behavior
No previous family history
Repetitive movements
Repetitive or self-injurious behavior

[ more ]



The underlying cause of autism spectrum disorder (ASD) is generally unknown. Scientists suspect that it is a multifactorial condition, meaning that a variety of factors (both genetic and environmental) likely contribute to the development of the condition.[1][2]

Known risk factors for ASD include:[4][1][2][3]

  • Male gender
  • Having a sibling with ASD
  • Having older parents (a mother who is 35 or older, and/or a father who is 40 or older when the baby is born)
  • Having certain genetic conditions (including Down syndrome, fragile X syndrome, and tuberous sclerosis)
  • Exposure to certain prescriptive medications during pregnancy (such as valproic acid, thalidomide)

Of note, no scientific evidence for a relationship between vaccines and autism has been identified.[1]


A diagnosis of autism spectrum disorder (ASD) may be suspected in young children who are not meeting typical social and language milestones. Although medical tests (i.e. blood tests, imaging studies, a hearing test) may be ordered to rule out other conditions that can be associated with similar features, there is not specific test available to confirm a diagnosis of ASD. Instead, a diagnosis is often based on guidelines from a medical book called Diagnostic and Statistical Manual of Mental Disorders. A team of specialists with knowledge of standardized testing of autism may evaluate the following abilities to support a diagnosis:[1][2][5]

  • Communication
  • Language
  • Motor skills
  • Speech
  • Success in school
  • Thinking abilities


Although there is currently no cure for autism spectrum disorder (ASD), available treatment programs significantly improve the outlook for most affected children. Treatment plans may include a combination of the following techniques, including:[1][2]

For more information about the treatment and management of ASD please visit the MedlinePlus or Medscape Reference websites.


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • The Autism Society of America is a support organization for individuals and families affected by autism spectrum disorders. Click on the link to view their information page on ASD.
    • You can obtain information on this topic from the Centers for Disease Control and Prevention (CDC). The CDC is recognized as the lead federal agency for developing and applying disease prevention and control, environmental health, and health promotion and education activities designed to improve the health of the people of the United States.
    • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
    • The Merck Manuals Online Medical Library provides information on this condition for patients and caregivers.
    • The National Human Genome Research Institute (NHGRI) website has an information page on this topic. NHGRI is part of the National Institutes of Health and supports research on the structure and function of the human genome and its role in health and disease.
    • The National Institute of Mental Health (NIMH) has information on this topic. NIMH is part of the National Institutes of Health and is dedicated to understanding, treating, and preventing mental illnesses.
    • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.

      In-Depth Information

      • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
      • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Autism spectrum disorder. Click on the link to view a sample search on this topic.


        1. Autism Spectrum Disorder. MedlinePlus. May 2016; https://medlineplus.gov/ency/article/001526.htm.
        2. James Robert Brasic, MD, MPH. Autism. Medscape Reference. November 2016; https://emedicine.medscape.com/article/912781-overview.
        3. Autism Spectrum Disorder. National Institute of Mental Health. October 2016; https://www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd/index.shtml.
        4. Facts About ASD. Centers for Disease Control and Prevention. March 2016; https://www.cdc.gov/ncbddd/autism/facts.html.
        5. Learning About Autism. National Human Genome Research Institute. November 2012; https://www.genome.gov/25522099.

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