Health Scan: Biological marker found for autism

Weizmann Institute researchers in cooperation with US universities find a method to identify biological signs of autism in young toddlers.

Child / kid / youngen / small human 311 (photo credit: Thinkstock/Imagebank)
Child / kid / youngen / small human 311
(photo credit: Thinkstock/Imagebank)
Neurologists and child development specialists have learned quite a lot about autism and its possible causes in recent years, but much remains poorly understood. It is usually diagnosed “late” – around the age of three or four, and the tests are still subjective.
Now Weizmann Institute of Science researchers, along with colleagues at Carnegie Mellon University and the University of California, San Diego, have found a method that can identify a biological sign of autism in young toddlers that could lead to early diagnosis. The research recently appeared in Neuron.
By scanning the brain activity of sleeping children, the scientists discovered that autistic brains exhibited significantly weaker synchronization between areas tied to language and communication, compared to that of non-autistic children.
“Identifying biological signs of autism has been a major goal for many scientists around the world, both because these may allow early diagnosis, and because they can provide important clues about the causes and development of the disorder,” says post-doctoral fellow Dr. Ilan Dinstein, working with Prof.
Rafael Malach, who headed this study at the Rehovot institute’s neurobiology department. While many scientists believe that faulty lines of communication between different parts of the brain are involved in autism disorders, there was no way to observe this in very young children, who are unable to lie still inside a functional MRI scanner while they are awake.
But work by Malach’s group and other research teams pointed to a solution. Their studies had shown that even during sleep, the brain does not actually switch off. Rather, its electrical activity switches over to spontaneous fluctuation coordinated across the brain’s two hemispheres; each point on the left is synchronized with its corresponding point in the right.
In sleeping autistic toddlers, the fMRI scans showed lowered levels of synchronization between the areas known to be involved in language and communication.
This pattern was not seen either in children with normal development or in those with simple delayed language development. In fact, the researchers found that this synchronization was strongly tied to the autistic child’s ability to communicate: The weaker the synchronization, the more severe the symptoms of autism. On the basis of the scans, the scientists were able to identify 70 percent of autistic children between the ages of one and three.
Dinstein concludes: “This biological measurement could help diagnose autism at a very early stage. The goal for the near future is to find additional markers that can improve the accuracy and reliability of the diagnosis.”
Moldy threat to health
Black mold on walls is not only unesthetic and smelly; this growth on moist surfaces can also be harmful to health. University of Cincinnati researchers write in the August issue of Annals of Allergy, Asthma & Immunology that babies who live in “moldy” homes are three times more likely to develop asthma by age seven than those living in homes without such conditions.
“Early life exposure to mold seems to play a critical role in childhood asthma development,” says Prof. Tiina Reponen, lead study author and an expert in environmental health at the Ohio university. “Genetic factors are also important to consider, since infants whose parents have an allergy or asthma are at the greatest risk of developing asthma.”
The university and Cincinnati Children’s Hospital Medical Center researchers analyzed seven years of comprehensive data for 176 children to evaluate the effects of mold exposure in early life as part of a long-term population-based study that included more than 700 children from the greater Cincinnati area. They analyzed the effects of environmental particles on childhood respiratory health and allergy development, and identified children who already in infancy were identified as being at high risk of developing allergies.
Mold exposure levels were measured using a DNA-based analysis tool developed by the US Environmental Protection Agency – the environmental relative moldiness index, which combines results of the analysis of 36 different types of mold. Eighteen percent of the children were found to be asthmatic at age seven. It is estimated that about 9% of school-age children in the US will develop asthma; however, studies have shown that rates are often higher in children from poor urban families. The disease cannot be accurately diagnosed until age seven.
”The symptoms of pediatric asthma range from a nagging cough that lingers for days or weeks to sudden shortness of breath and wheezing that requires emergency treatment,” says allergist Dr. David Bernstein, a study co-author. “If a young child’s symptoms persist, that’s a clue that it could be asthma.”
Common symptoms of asthma include coughing, especially at night; a wheezing or whistling sound when exhaling; difficulty breathing or rapid breathing that causes the skin around the ribs or neck to pull in tightly; and frequent colds that settle in the chest.
“This study should motivate expectant parents – especially if they have a family history of allergy or asthma – to reduce the mold burden in their homes,” adds Reponen.