Towards the understanding of Down syndrome using mouse models.

Down syndrome (DS) is the most common cause of mental retardation. Several DS mouse models with partial trisomy 16 homologous to human chromosome 21 have been developed, and our research group has been studying those mouse models. We have shown a dosage-dependent overexpression of genes in the trisomic region of the mouse. We have also described abnormalities including increased oxidative stress, increased lipid peroxidation, mitochondrial dysfunction, tau-hyperphosphorylation and overactivation of its phosphatases, impaired developmental and adult neurogenesis, histological abnormalities in brains including ventricle enlargements and minor neurodegenerations in those mice. These observations may contribute to the identification of responsible genes and understanding of molecular pathology of Down syndrome.