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Nine TS subjects had mosaic 45,X karyotypes,and 9 had non-mosaic 45,X.The TS group had significantly lower scores than the controls for all the Wechsler adult intelligence scale tests,except verbal comprehension and reading level.The greatest difference was in visuospatial construction (mean 90[DS 12]vs 118[13],p<0.0001).The TS subjects also had a greater discrepancy than controls between verbal and performance intelligence quotients(9[8]vs-5[9],p<0.0001).We found that TS subjects had significantly smaller values than controls in MRI-measured volumes of hippocampus,caudate,lenticular,and thalamic nuclei,and parieto-occipital brain matter,on both sides.Women with mosaic TS had values between the full TS and control groups for cerebral hemisphere and lenticular and thalamic nuclei volume and for verbal ability.Within the mosaic TS group, visuospatial ability was significantly correlated with the percentage of lymphocytes that had the 45,X karyotype.Hippocampal volume and memory test scores were significantly lower in mosaic and non-mosaic 45,X TS subjects than in controls.We postulate that in human beings the X chromosome plays an important part in the development and aging of grey matter in striatum, diencephalon,and cerebral hemispheres. |
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