About Careers MedBlog Contact us
Possible Mechanisms of Autism Development Explored

Possible Mechanisms of Autism Development Explored

Written by Dr. Simi Paknikar, MD
Medically Reviewed by 
The Medindia Medical Review Team on September 13, 2017 at 6:49 PM
Font : A-A+


  • Autism has been earlier linked to the presence of severe infection and inflammation during pregnancy
  • Research on mice evaluated the possible mechanisms for this link
  • Reduced number of interneurons in a particular part of the brain and the presence of segmented filamentous bacteria in the maternal digestive tract may play a role

Studies have explored the role of maternal infection and inflammation in the development of autism in the offspring.

Autism is a developmental condition characterized by problems with communication and social interaction. The child shows repetitive behavior and appears to be in his/her own world, but usually has normal intelligence. The exact causes of autism are not known, though genetic and environmental factors have been implicated. A better understanding of the causes could help to take steps to prevent the condition, which is important since it does not have a definite cure.

Listen to this article

Possible Mechanisms of Autism Development Explored

The presence of infection during pregnancy appears to influence the development of autism. It has been earlier suggested that severe infection during pregnancy that requires hospitalization could increase the risk of giving birth to an autistic child. A study from Denmark indicated that viral infections during the first trimester of pregnancy increased the risk of autism three times, while serious bacterial infections during the second trimester increased the risk 1.42 times.

The link between inflammation during pregnancy and the development of brain changes has been suggested by another study in mice. In the study, a type of immune cells called the Th17 cells released a chemical called IL-17 which appeared to affect certain parts of the fetal brain, resulting in 'patches'.

In one study on mice with behavioral problems, the scientists studied a part of the somatosensory cortex where patches commonly occur called S1DZ. The somatosensory cortex is the part of the brain that is responsible for processing information obtained from our surroundings. They found that:
  • In the patches, a type of nerve cells called interneurons are reduced. Interneurons are nerves that connect other nerves, and control their excitation or inhibition.
  • The reduced number of interneurons caused an increased excitement in the S1DZ
  • When the activity of the brain was normalized, the behavioral changes were reversed
  • When the S1DZ was overstimulated in normal mice, the behavioral symptoms appeared, thereby indicating the role of the part of the brain in the development of behavioral symptoms
  • When the neurons connecting the S1DZ to two other areas, the temporal association area and the striatum, were inhibited, the problems with sociability and repetitive behaviors in the mice were overcome
Another study in mice demonstrated the role of inflammation during pregnancy in the development of behavioral problems in mice. The scientists found that:
  • The presence of segmented filamentous bacteria in the digestive tract, which are actually harmless, was associated with behavioral problems and the patches in the brain in the offspring
  • The IL-17 appeared within a day of stimulating the immune system, suggesting that it was produced by pre-existing immune cells
  • Treatment with antibiotics acting against the segmented filamentous bacteria, resulted in normal mice

Implication of these studies

  • Bacteria in the digestive tract during pregnancy can cause inflammation and result in behavioral problems and brain changes
  • It could be possible to reduce the risk of autism if the function of bacteria in the maternal digestive tract that stimulate inflammation is blocked
Further studies in humans are necessary to validate the findings of the two studies in humans. Scientists also warn that though severe maternal infection could be a cause of autism, it is not the only cause, and therefore eliminating bacteria may not be the answer to preventing all cases of autism.

Reference :
  1. Nature, September 13,(2017)

Source: Medindia

Cite this Article   close



Recommended Reading

Latest Health In Focus

Can Injury to the Brain Lead to Brain Cancer?
Head injury due to trauma can cause brain cancer by triggering changes in mature brain cells called astrocytes, states the research.
Physical Strain at Work Can Give You a Higher Sperm Count
Sperm count, testosterone levels, and male fertility are higher in men who lift or move heavy objects at work
A Non Invasive Screening Test for Fetal Genetic Anomalies: Cell-Free DNA Testing
Cell-free DNA analysis of maternal plasma is easy ,non- invasive and highly effective in detecting fetal chromosomal and genetic abnormalities in antenatal mothers
Include Eggs in Your Diet to Lower the Risk of Heart Disease
Including eggs in your diet can reduce the risk of heart disease by 60-75% and also improve blood sugar levels
Possible Genetic Link Between Migraine and Blood Sugar Levels
A new genetic link between migraine and mismanaged blood sugar levels is confirmed. It can help discover new treatments
View All
This site uses cookies to deliver our services.By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use  Ok, Got it. Close

Possible Mechanisms of Autism Development Explored Personalised Printable Document (PDF)

Please complete this form and we'll send you a personalised information that is requested

You may use this for your own reference or forward it to your friends.

Please use the information prudently. If you are not a medical doctor please remember to consult your healthcare provider as this information is not a substitute for professional advice.

Name *

Email Address *

Country *

Areas of Interests