ABSTRACT
This chapter describes the animal models that have provided valuable insights into the pathogenesis of many human conditions in which mental retardation is a major component. Therefore, various mouse models have been generated and studied with a view of gaining insight into the molecular, genetic, and/or developmental mechanisms that underlie the morphological, histological, biochemical, and immunological abnormalities that occur in Down’s syndrome (DS). Reduction in cerebellar volume is invariant in individuals with DS, and this completely penetrant phenotype of DS is accurately recapitulated in the Ts65Dn mouse model. The development and analysis of segmental mouse models are proving to be quite promising in meeting the challenge to understand the role of individual genes in the pathogenesis of the neurological and behavioral phenotype of DS. Mouse models of human trisomy 21 provide the substance for identifying corresponding consequences of gene-dosage imbalance in mouse and human.
