International Meeting for Autism Research (May 7 - 9, 2009): MAOA, DΒH and 5-HTT Variants and Autism Spectrum Disorders in the CHARGE Samples
Start | Browse by Day or Format | Author Index

MAOA, DΒH and 5-HTT Variants and Autism Spectrum Disorders in the CHARGE Samples

Friday, May 8, 2009
Northwest Hall (Chicago Hilton)
12:00 PM
F. Tassone , Biochemistry and Molecular Medicine and the M.I.N.D. Institute, UC Davis, Davis, CA
L. Qi , Department of Public Health Sciences, School of Medicine, University of California, Davis, California, 95616, USA, UC Davis, Davis, CA
W. Zhang , Biochemistry and Molecular Medicine, UC Davis, Davis, CA
R. L. Hansen , Pediatrics and the M.I.N.D. Institute, University of California at Davis, Sacramento, CA
I. Hertz-Picciotto , Public Health Sciences and the M.I.N.D. Institute, University of California at Davis, Davis, CA
I. N. Pessah , M.I.N.D. Institute and Department of Veterinary Medicine: Molecular Biosciences, University of California at Davis, Davis, CA
Background: There is strong evidence that genetic factors play an important role in the development of autism.However, several research groups, often with different results, have studied a number of candidate genes, which emphasizes the complexity of the underlying etiology and pathophysiology of the disorder.

Objectives: We examined three loci, the serotonin transporter (5-HTT), the dopamine hydroxylase (DβH) and the Monoamine Oxidase A (MAOA) for association with autism using partecipants from the CHARGE Study. The CHARGE (Childhood Autism Risks from Genetics and the Environment) Study is the first large-scale population-based case-control study investigating both environmental and genetic contributions to autism risk.

Methods: The study has been recruiting families with children aged 2-5 years from three groups: autism (AU), autism spectrum disorder (ASD), and from typically developmenting (TD) controls from the general population.
We tested for association between each of the three microsatellites and autism in a sample of 128 children with AU, 61 with ASD, and 167 TD. We also conducted family-based association test transmission disequilibrium in these families (189 trio families with a child with ASD or autism and 167 families with a typically developing child).

Results: No significant transmission disequilibrium was found for any of the microsatellites in families of children with autism and ASD. This analysis was underpowered due to the preponderance of homozygous mothers in this sample, who do not contribute to transmission analyses. Based on the case-control association analysis, neither the 5-HTT nor the DΒH genes showed any statistically significant association with autism. However, among White and Hispanic males, the children carrying allele 4 of the MAOA gene showed a 2-fold higher risk of AU (or AU+ASD combined) than those carrying allele 3 (multiple logistic regression adjusting for race and maternal age, 95% CI = 1.12, 3.65, p = 0.02 for AU vs. TD, and 95% CI = 1.19, 3.53, p = 0.01 for AU+ASD vs. TD).

Conclusions: These results suggest a potential role of the functional MAOA-uVNTR alleles in autism spectrum disorders.
Understanding the molecular mechanisms linked to the functional polymorphisms variants in the neurotransmitter pathways and understanding the role of the environment contribution may help to elucidate how these polymorphisms can determine the behavioral outcome.

See more of: Poster III
See more of: Poster Presentations