Olfactory bulb mitral cell dendritic pruning abnormalities in a mouse model of the Fragile-X mental retardation syndrome: further support for FMRP's involvement in dendritic development.

The Fragile-X mental retardation syndrome is the leading form of inherited mental retardation. Dendritic analysis in a mouse model (FraX) found abnormal pruning in somatosensory cortex. To further characterize dendritic abnormalities and assess their occurrence in other brain regions, we examined mitral cells in FraX mice olfactory bulbs. FraX mice exhibited dendritic abnormalities consistent with somatosensory cortex, suggesting that deficient pruning is found in multiple brain regions.