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Autism Linked to Testosterone?

New research links autism to testosterone levels in children.I just read an interesting article by Dr. Baron–Cohen who is a professor of developmental psychology and the director of the Autism Research Centre at the University of Cambridge, England.  He is the principle architect of a theory which suggests that autism is linked to in utero exposure of the fetus to very high levels of testosterone.

This interesting hypothesis is that these very high levels of in utero testosterone can lead to extreme masculinization of the brain and the mind of the newborn. In Dr. Baron-Cohen’s words, “autism can be thought of as a case of extreme male brain”.  This seemed fascinating to me, so I continued to read on. According to Dr. Baron-Cohen, the hormone testosterone and the genes that regulate testosterone during fetal development may be part of the link to the cause of autism. Although it is known that autism is likely due to complex and multifactorial issues, Dr. Baron-Cohen has found that fetal testosterone levels are typically twice as high in males as in females, and testosterone levels may vary up to 20 times in male fetuses. Given that the prevalence of autism spectrum conditions is about 1% in the general population, and that classic autism has a male: female ratio of 4:1, and Asperger’s syndrome is 9:1, the increased testosterone levels may be significant. Dr. Baron-Cohen has been conducting an ongoing study looking at 235 developing children whose fetal testosterone levels were known from maternal amniocentesis.  He has followed them for 8 years and had parents rate their children for autistic traits.  He found that the number of autistic traits a child displayed correlated with their fetal testosterone level, regardless of their sex. He also reported that earlier studies done on these children at 12 months of age, showed that those babies with higher testosterone levels were less likely to make eye contact with the mothers, and at age 2 these children had  more limited vocabulary and language development than did those infants with lower fetal testosterone levels. So, many of the hallmarks of autistic spectrum disorders include social and communication difficulties, narrow interests, and extreme need for routine. Many would view these characteristics as being extreme “male” interests and behaviors. Does this in any way relate to those higher fetal testosterone levels?  Are these gender differences due to cultural and social influences?  These are very interesting questions and will need even more study. Dr. Baron–Cohen and other investigators will need to continue to research this very important, yet preliminary hypothesis, to see if they continue to find a correlation between fetal testosterone levels and autistic symptoms.   Any information that brings us closer to solving the puzzle of autism is very exciting.  I look forward to reading further data as it becomes available. That's your daily dose for today.  We'll chat again tomorrow. Send your question or comment to Dr. Sue!

Daily Dose

In The News: Vaccine Safety

Vaccine safety in the headlines this week.There have been several articles in the news recently related to vaccines and concerns over their safety.

In the last several days the special master appointed by the United States Court of Federal Claims ruled that “the theory of vaccine–related causation and autism is scientifically unsupportable”.   The special “vaccine court” rejected the plaintiff’s theory linking thimerosal, a preservative previously used in vaccines, with the development of autism spectrum disorders in children. In a previous case before the court in 2009, the court also discounted parent’s claims that the MMR vaccine and thimerasol caused the development of autism.  These rulings continue to refute a connection between childhood vaccines and autism. It should be noted that thimerasol is no longer used in vaccines, and despite this autism incidence has risen.  The argument that the MMR vaccine alone could cause autism has also been refuted and last month the Lancet officially retracted the Wakefield paper from 1998 that started the idea that vaccines and autism are somehow related. Earlier this month, the United States Supreme Court announced that it will hear a case in which a family argues that there should be legal recourse beyond the administrative process set up by the National Childhood Vaccine Injury Act (a law passed in 1986 to protect vaccine manufacturers from costly lawsuits). This family sued over a DPT (diphtheria, pertussis, and tetanus) shot, as a cause of their daughter’s seizure disorder. This case has been in the courts for over 15 years and the family has been denied compensation because they have been unable to prove “causation” between the vaccine and their child’s seizures. This is a pivotal case for both drug companies who want to clarify the legal issues surrounding vaccines, and parents who still believe that vaccines have caused injury to their children. Despite the literature and science surrounding vaccine safety,  a survey in the March issue of Pediatrics still show that fears may linger among parents regarding vaccines and safety.  In the study, 90 percent of parents with young children agreed that vaccines protected children from disease, but 25 percent continued to think that vaccines might cause autism. I continue to hear concerns from parents, but hopefully with logic, science and now the courts behind vaccines, parents will choose vaccines to protect their children and we will not see outbreaks of vaccine preventable diseases in this country. That's your daily dose for today. We'll chat again tomorrow.

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