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Asperger syndrome

Synonym(s) -
Prevalence -
Inheritance Multigenic/multifactorial
Age of onset Childhood
  • F84.5
  • C0236792
  • D020817
  • 10003484


Asperger syndrome (AS) is a neurodevelopmental disorder, generally considered to be an autism spectrum disorder (ASD), and is characterized by difficulties in social-emotional reciprocity, deficits in non-verbal communication and developing understanding and maintaining relationships, restricted patterns of behavior and interests, and hyper and hypo-reactivity to sensory experiences.

The exact prevalence is unknown due to a lack of consistent criteria to clearly distinguish AS from ASD. ASD has an incidence in the general population of approximately 1/68. AS is not considered to be a rare disease. Males seem to be more frequently affected than females with a ratio of 2:1.

Before the age of 4, AS is usually asymptomatic and children have normal or near-normal language development. However, they may have difficulty with the pragmatic (i.e. conversational) aspects of language, have abnormal or pedantic content and focus conversations on a preferred topic of interest. They also lack the understanding of semantic content (i.e. irony, jokes). Unusual reactions to sensory input (i.e. noise, light, aromas, and temperature) can often be first recognized during infancy. Diagnosis of AS is delayed and usually occurs around the age of 7 (but some remain undiagnosed until adulthood) when social demands exceed limited capacities or may be marked by learned strategies. Impaired social interactions (lack of social awareness, lack of interest in socializing, inability to socialize/make friends) cause many children to be socially isolated. Eye contact may be elusive or fixed when conversing with others. Behavior disturbances may present before or after the appearance of atypical social skills and include repetitive interests (overfixation on a preferred subject), cognitive rigidity (i.e. intolerance to changes in routine), and relative difficulty completing chores or daily tasks, considering the person's intellectual abilities. Other conditions that can be associated with AS include anxiety disorders, disruptive behavior disorders (i.e. aggression), attention deficit hyperactivity disorder, depression (and other mood disorders), and sleep disturbances. Intelligence is within the normal range.

The exact etiology of AS is unknown but like ASD, genetic and neurobiological factors are thought to play a role in the development of this disease. Epigenetic factors and exposure to environmental modifiers may also account for a few cases.

Diagnosis of AS is based on a clinical assessment by a multidisciplinary team and a thorough investigation into the patient's health and developmental history combined with the use of a formal diagnostic tool. The diagnostic guidelines most often followed are the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5), and the International Classification of Diseases (ICD-10). Magnetic resonance imaging, electroencephalography and chromosome analysis may be useful in excluding other similar disorders.

The main differential diagnoses of AS include early-childhood autism, attention deficit-hyperactivity disorder, personality disorders (i.e. schizoid, schizotypal, borderline) social anxiety disorders, and obsessive-compulsive disorders. Normal or near normal language development and normal intelligence differentiates AS from other ASDs.

There is no cure for AS and treatment is symptomatic. Management relies on long-term remedial educational (i.e. social skills training) and therapy programs (i.e. speech and language therapy). Psychopharmacologic interventions may be necessary in those with associated psychological disorders. Cognitive behavior therapy can be successful in treating mood disorders.

AS is considered to be a life-long disorder and outcome varies between patients. With proper support and education, symptoms can diminish over time and patients can enjoy a good quality of life, but difficulties in social interactions may persist.

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