The following slide presentation was given by Marie Bristol-Power, PhD, who serves as the Special Assistant for Autism, in the Office of the Director at the NICHD. The summary below was adapted from her slide presentation at the March 8, 2001, meeting of the Institute of Medicine (IOM) Immunization Safety Review Committee, held at the National Academy of Sciences in Washington, DC. Please note that each bold heading represents one slide.

Autism-No single cause; no single cure
Autism is likely the result of a variety of factors, such as:

• Genetic
• Infectious
• Neurologic
• Metabolic
• Immunologic
• Environmental

Etiological Hypotheses for Autism

• Assuming there is no single cause, there will also be no single cure.
• Current research seems to support two etiologies of autism: Early Onset of Autism vs. regressive autism.
• Regression occurs in other disorders, such as Rett Syndrome and Glutaric Aciduria; researchers are using these as models for investigation.

Some possible mechanisms for immune developmental disorders

• Inadequate protection against viral or other pathogens results in fetal/child infection
• Maternal immune defect results in inadequate protection or autoimmune attack of developing fetal brain
• Pre- or postnatal genetic immune defect in child, plus antigenic trigger, result in autoimmune attack of the brain

Immune findings in autism

Limitations of immune hypotheses of autism

• No autopsy studies of brains from individuals with autism have demonstrated immune pathology.
• Comparisons across studies are difficult because autism assessment, control groups, and immune measures vary across studies.
• No immune mechanism has been elaborated to explain how immune defects alter brain anatomy or physiology in a specific pathway that results in autism.
• There is no immune animal model for autism, which makes it much more difficult to study in a lab.
• Treatment studies do not support the clinical use of IVIG, which would support a immunological factor in autism.

Update on the NICHD Collaborative Programs of Excellence in Autism (CPEAs)

Longitudinal Cohort Study of Environmental Effects on Child Health and Development