Testosterone

Sex Differences in Autism Spectrum Disorders

Source: 
Current Opinion in Neurology
Date Published: 
February 13, 2013
Abstract: 

A review of current research shows that ASD affects females less frequently than males and suggests this difference may be due to several sex-differential genetic and hormonal factors.

Prenatal Versus Postnatal Sex Steroid Hormone Effects on Autistic Traits in Children at 18 to 24 Months of Age

Source: 
Molecular Autism
Date Published: 
December 11, 2012
Abstract: 

Cambridge researchers are investigating the link between pre- and postnatal hormone levels and autistic traits later in life.

Researchers Reveal First Autism Candidate Gene That Demonstrates Sensitivity to Sex Hormones

Source: 
Journal of Molecular Psychiatry, Hu et al.
Date Published: 
March 2011
Year Published: 
2011

 

George Washington University researchers have found that male and female sex hormones regulate expression of an important gene in neuronal cell culture through a mechanism that could explain not only higher levels of testosterone observed in some individuals with autism, but also why males have a higher incidence of autism than females.

The gene, RORA, encodes a protein that works as a "master switch" for gene expression, and is critical in the development of the cerebellum as well as in many other processes that are impaired in autism. Dr. Hu's earlier research found that RORA was decreased in the autistic brain. In this study, the research group demonstrates that aromatase, a protein that is regulated by RORA, is also reduced in autistic brains.

This is significant because aromatase converts testosterone to estrogen. Thus, a decrease in aromatase is expected to lead in part to build up of male hormones that, in turn, further decrease RORA expression, as demonstrated in this study using a neuronal cell model. On the other hand, female hormones were found to increase RORA in the neuronal cells. The researchers believe that females may be more protected against RORA deficiency not only because of the positive effect of estrogen on RORA expression, but also because estrogen receptors, which regulate some of the same genes as RORA, can help make up for the deficiency in RORA.

Researchers Reveal First Autism Candidate Gene That Demonstrates Sensitivity to Sex Hormones

Source: 
Science Daily
Date Published: 
February 17, 2011
Abstract: 

George Washington University researcher, Dr. Valerie Hu, Professor of Biochemistry and Molecular Biology, and her team at the School of Medicine and Health Sciences, have found that male and female sex hormones regulate expression of an important gene in neuronal cell culture through a mechanism that could explain not only higher levels of testosterone observed in some individuals with autism, but also why males have a higher incidence of autism than females.

Linkage, Association, and Gene Expression Analyses Identify CNTNAP2 as an Autism-Susceptibility Gene

Source: 
American Journal of Human Genetics, Alarcon, Abrahams, et al.
Date Published: 
January 2008
Year Published: 
2008

Autism is a genetically complex neurodevelopmental syndrome in which language deficits are a core feature. We describe results from two complimentary approaches used to identify risk variants on chromosome 7 that likely contribute to the etiology of autism. A two-stage association study tested 2758 SNPs across a 10 Mb 7q35 language-related autism QTL in AGRE (Autism Genetic Resource Exchange) trios and found significant association with Contactin Associated Protein-Like 2 (CNTNAP2), a strong a priori candidate. Male-only containing families were identified as primarily responsible for this association signal, consistent with the strong male affection bias in ASD and other language-based disorders. Gene-expression analyses in developing human brain further identified CNTNAP2 as enriched in circuits important for language development. Together, these results provide convergent evidence for involvement of CNTNAP2, a Neurexin family member, in autism, and demonstrate a connection between genetic risk for autism and specific brain structures.