The use of microarrays to study childhood developmental brain disorders

An estimated 9 to 22% of the pediatric age group are affected by the extremely broad range of childhood neurological disorders, which includes autism and other pervasive developmental disorders (PDD). As with most all of the neurodevelopmental disorders, the PDD spectrum disorders demonstrate a tremendous degree of clinical, biochemical, and genetic heterogeneity. In the great majority of cases, the underlying molecular defects are not known and both diagnosis and appropriate treatment remain challenging. Gene expression profiling using DNA microarrays is a useful tool to characterize cellular samples from patients with childhood neurological disorders. There are two principal goals in the characterization of transcriptional changes in these disorders: 1) Accurate molecular diagnosis of disorders in the absence of clear clinical or biochemical diagnostic markers. Additionally, analysis of transcriptional patterns can be used to generate sub-classifications of individual disorders. 2) Identification of cellular systems that are disrupted in the disorder. Changes in the expression of individual genes as well as functionally related groups of genes can delineate biochemical pathways that are perturbed in a disorder. Both of these goals are ultimately directed at the development of effective therapeutic strategies. This review describes recent advances in these areas, discussing issues relevant to the study of gene expression in pediatric neurodevelopmental disorders.