TY - GEN ID - cogprints6539 UR - http://cogprints.org/6539/ A1 - Bauchwitz, Dr. Robert P. Y1 - 2004/05/10/ N2 - Fragile X Syndrome is the most common form of inherited mental retardation. It is also known for having a substantial behavioral morbidity, including autistic features. In humans, Fragile X Syndrome is almost always caused by inactivation of the X-linked FMR1 gene. A single knockout mouse model, fmr1-tm1Cgr, exists. In this report we further characterize the cognitive and behavioral phenotype of the fmr1-tm1Cgr Fragile X mouse through the use of F1 hybrid mice derived from two inbred strains (FVB/NJ and C57BL/6J). Use of F1 hybrids allows focus on the effects of the fmr1-tm1Cgr allele with reduced influence from recessive alleles present in the parental inbred strains. We find that the cognitive phenotype of fmr1-tm1Cgr mice, including measures of working memory and learning set formation that are known to be seriously impacted in humans with Fragile X Syndrome, are essentially normal. Further testing of inbred strains supports this conclusion. Thus, any fmr1-tm1Cgr cognitive deficit is surprisingly mild or absent. There is, however, clear support presented for a robust audiogenic seizure phenotype in all strains tested, as well as increased entries into the center of an open field. Finally, a molecular examination of the fmr1-tm1Cgr mouse shows that, contrary to common belief, it is not a molecular null. Implications of this finding for interpretation of the phenotype are discussed. PB - Blackwell Munksgaard KW - audiogenic seizure KW - Barnes maze KW - Fmr1 RNA KW - Fragile X KW - hybrid mouse strain KW - Morris water maze KW - olfactory sequence learning KW - open field KW - radial maze KW - working memory TI - A phenotypic and molecular characterization of the fmr1-tm1Cgr Fragile X mouse SP - 337 AV - public EP - 359 ER -