Early marker for autism found in the placenta

Jun 27 2006

A team from Yale School of Medicine have found an abnormality in the placenta which could be the first indication of autism and they believe the discovery could lead to a diagnosis of the condition at birth, rather than the standard age of two or older.

Autism Spectrum Disorder (ASD) is a developmental disorder that has profound effects on socialization, communication, learning and other behaviours and usually develops by age two.

It affects one in every 200 children and the earlier the diagnosis is made, the more effective the treatment can be; experts say a diagnosis at birth would be ideal.

Senior author of the study Harvey J. Kliman, M.D., research scientist in the Department of Obstetrics, Gynecology & Reproductive Sciences at the Yale School of Medicine, had found in earlier work that there was a unusual feature in the placentas from children with Asperger Syndrome, an ASD condition which, like autism, impairs the ability to relate to others.

The abnormality was an unusual folding of the surface layers of the placenta, that tends to trap a class of cells called trophoblasts as "inclusions" within the layers which can be easily seen with a microscope.

By working with researchers at the Yale Child Study Center who had access to many cases of children with ASD, Kliman was able to design a study to examine whether the trophoblast inclusions, was a marker for ASD.

The research team compared placentas from 13 children with ASD tissue samples which had been stored at birth, to those from 61 unaffected children for the presence of trophoblast inclusions and found that the placentas from ASD children were three times more likely to have the inclusions.

Dr. Kliman says they already knew that trophoblast inclusions were increased in cases of chromosome abnormalities and genetic diseases, but they had no idea whether they would be significantly increased in cases of autism spectrum disorder.

They say however that the test at present is not specific enough to act as an early warning of autism but they plan to carry out larger studies which will examine the placentas of the children in the study in greater detail.

If their findings are then confirmed it may be an indication that a child should be checked by a specialist to determine the presence of ASD as soon as possible.

The findings are reported in the June 26 online issue of Biological Psychiatry.