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autism spectrum disorder (ASD)


  • autism spectrum disorder (ASD) is a range of severities of childhood development disorders, in particular, deficits in non-verbal communication skills and impaired social interaction
  • ASD is a subset of the broader autism phenotype, which describes individuals who may not have ASD but do have autistic-like traits, such as social deficits
  • ~1/5th of cases are due to Asperger's syndrome
  • Fragile X syndrome is the most common known single-gene cause of autism and the most common inherited cause of mental retardation among boys.
    • is caused by expansion of the CGG trinucleotide repeat affecting the Fragile X mental retardation 1 (FMR1) gene on the X chromosome causing a failure to express the fragile X mental retardation protein (FMRP), which is required for normal neural development and this results in:
      • a spectrum of intellectual disability ranging from mild to severe
      • elongated face
      • large or protruding ears
      • large testes (macroorchidism)
      • behavioral characteristics such as stereotypic movements (e.g. hand-flapping)
      • social anxiety

proposed DSM V changes

New name for category, “autism spectrum disorder”, which includes autistic disorder (autism), Asperger’s disorder, childhood disintegrative disorder, and pervasive developmental disorder (PDD) not otherwise specified.

Must meet criteria A, B, C, and D:

A. Persistent deficits in social communication and social interaction across contexts, not accounted for by general developmental delays, and manifest by all 3 of the following:

1. Deficits in social-emotional reciprocity; ranging from abnormal social approach and failure of normal back and forth conversation through reduced sharing of interests, emotions, and affect and response to total lack of initiation of social interaction,

2. Deficits in nonverbal communicative behaviors used for social interaction; ranging from poorly integrated- verbal and nonverbal communication, through abnormalities in eye contact and body-language, or deficits in understanding and use of nonverbal communication, to total lack of facial expression or gestures.

3. Deficits in developing and maintaining relationships, appropriate to developmental level (beyond those with caregivers); ranging from difficulties adjusting behavior to suit different social contexts through difficulties in sharing imaginative play and in making friends to an apparent absence of interest in people

B. Restricted, repetitive patterns of behavior, interests, or activities as manifested by at least two of the following:

1. Stereotyped or repetitive speech, motor movements, or use of objects; (such as simple motor stereotypies, echolalia, repetitive use of objects, or idiosyncratic phrases).

2. Excessive adherence to routines, ritualized patterns of verbal or nonverbal behavior, or excessive resistance to change; (such as motoric rituals, insistence on same route or food, repetitive questioning or extreme distress at small changes).

3. Highly restricted, fixated interests that are abnormal in intensity or focus; (such as strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests).

4. Hyper-or hypo-reactivity to sensory input or unusual interest in sensory aspects of environment; (such as apparent indifference to pain/heat/cold, adverse response to specific sounds or textures, excessive smelling or touching of objects, fascination with lights or spinning objects).

C. Symptoms must be present in early childhood (but may not become fully manifest until social demands exceed limited capacities)

D. Symptoms together limit and impair everyday functioning.

autism.txt · Last modified: 2012/09/05 05:34 by gary1