Testosterone in the womb linked to autism

Sep 12 2007

According to a recent study testosterone may be implicated in autism.

Researchers in Britain say children exposed to high levels of testosterone in the womb show more autism-related traits when they are older.

Researchers at Cambridge University say the findings suggest that the male hormone may play a key role in the complex brain disorder.

The researchers believe the results reinforce findings from tests on animals and also support the hypothesis that higher levels of testosterone may contribute to autism.

Animal research has previously linked brain development to foetal testosterone levels, and some believe the hormone may play a causal role in autism.

Professor Simon Baron-Cohen, director of the Autism Research Centre at the university, who worked on the study says although the findings of the research show promise they did not show a direct link between autism and testosterone and he suggests other factors could also be involved.

None of the 235 children in the study had autism.

Baron-Cohen says the ongoing research does show it is a significant correlation and remains significant after controls for other factors were applied.

The cause of the spike in testosterone is unclear, but environmental factors could be a factor.

He says that the hormone could be affecting the brain through altering neural cell connectivity and chemicals that carry messages, known as neurotransmitters.

The symptoms of Autism are wide and range from mild awkwardness to severe disability and mental retardation.

A recent survey found that 1 in every 150 U.S. children has autism or an autism spectrum disorder, a less severe condition related to autism, such as Asperger's.

No one knows what causes the complex developmental disorder which includes problems with social interaction and communication; it is incurable and is managed with behaviour therapy and medication.

For the study the Cambridge researchers measured fetal testosterone levels from pregnant women who had amniotic fluid taken for other reasons.

Later when the children reached eight years old, the researchers used questionnaires to see whether they preferred social to solitary activities and how empathetic they were.

In this way they were able to measure traits, that in an extreme form, are indicative of autism.

The study found that children with higher levels of fetal testosterone were better at remembering patterns but not as interested in socializing.

Baron-Cohen says the next step is to collaborate with Danish researchers to tap a biological bank that has about 90,000 amniotic fluid samples to test whether there is a direct link between fetal testosterone and autism.

He says this may provide a marker to help tell who might be at risk.

The work is linked to Professor Baron-Cohen's hypothesis that autism is a version of the extreme male brain.

A large study published earlier this year suggested that autism has numerous genetic causes and experts are in agreement that autism is likely caused by environmental factors working on a child with a genetic predisposition; testosterone in the womb might be one such factor.

The research was presented at the BA Festival of Science in York.