| SUBJECT |
In late 09.99, author et al reported that the great majority of Rett syndrome cases are caused by the mutation of a single gene on the X chromosome. Specifically the said genetic abnorma lity interferes with the operation of one of the many biochemical switches that regulate how genes are expressed. The researchers found that the disorder results from the mutation of the gene that makes methyl cytosine binding protein 2 (MECP2). MECP2 is the lynchpin of proteins needed to switch off a group of genes It is speculated that in the absence of this genetic switch, certain genes fail to shut down, & excessive amounts of otherwise beneficial proteins are made. The molecular events leading to a child decline can be explained by the overexpression of certain genes that govern the dev. of the nervous system. This overexpression may lead to defective maturation of the brain & nervous system. This idea is supported by biochemical brain analyses that demonstrate reduced amounts of the neurotransmitters acetylcholine, noradrenaline, dopanmine, serotonin, & glutamate in certain regions of the cerebral cortex & the basal ganglia in children with Rett syndrome. In addition, deficiency of growth factors required for the maturation of the brain & spinal cord is thought to play a role in triggering certain changes associated with the disease |
| UPDATE | 12.00 |
| AUTHOR | Zoghbi Huda Y.; prof. of pediatrics & molecular & human genetics at Baylor College of Medicine |
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