Down Syndrome: A Disorder of Histogenesis

Downs syndrome (DS), caused by triplication of chromosome 21 (trisomy 21), is the most common genetic cause of mental retardation. Abnormalities in histogenesis, neuron proliferation, and synaptic development underlie the cognitive deficits seen in DS individuals and changes in these processes begin during prenatal life. Ts16 and Ts65Dn mouse models of DS enable investigation of the links between prenatal morphogenetic disturbances and the postnatal neurobehavioral sequelae in DS and have therefore greatly advanced the understanding of the central nervous system development in DS.