Researchers have proposed a new hypothesis on the cause of autism, suggesting a mixed epigenetic and genetic and mixed de novo and inherited (MEGDI) model. Their hypothesis, and evidence to support it, will be published September 8, 2004 in the online edition of the American Journal of Medical Genetics Part A, and will be available via Wiley InterScience at http://www.interscience.wiley.com/journal/ajmg
The role of genetics in autism is believed to be significant because twin studies have found that identical twins, who have the same DNA, are much more likely to share the diagnosis than fraternal twins. However, experts have not yet identified the specific genetic components related to autism, and many experts believe that multiple genes are involved.
Researchers, led by Yong-hui Jiang of Baylor College of Medicine in Houston, propose that most cases of autism can be explained by a complex model for genetic malfunction that may or may not include an altered DNA sequence. Where the DNA sequence is intact, the researchers believe that gene expression could be faulty. They suggest that some of these genetic factors are inherited, and others occur de novo in genes of the autistic person. In this study, they formulate a five-part hypothesis on the cause of autism:
Based on the evidence of parent-of-origin effects, they propose that there is a major epigenetic (related to gene expression, not sequence) component in the etiology of autism involving genetic imprinting.
They suggest that epigenetic and genetic factors (both de novo and inherited) cause autism through dysregulation of two or more principal genes, one of which maps within chromosomes 15q11-q13, with the Angelman gene encoding E6-AP ubiquitin-protein ligase (UBE3A) being the strongest candidate in this region
They propose that the dysregulation of UBE3A involves some combination of overexpression, gene silenPage: 1 2 3 Related biology news :1
Contact: David Greenberg
John Wiley & Sons, Inc.
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