[Neuropathology of the XXXX ].

@entity1 @entity154 @entity1032 @entity550 @entity3664 @entity10579 @entity2689 @entity76
We report the neuropathologic examination of a neonatal case of @entity2689 (45,XO). We have found some mild irregularities in the cortical organization, notably in frontal and hippocampal regions. In the frontal @entity550 affected particularly the more superficial layers essentially sparing the migrating process which was largely achieved in its fundamental phases. The hippocampal dentate gyrus appeared abnormally infolded. The cerebellum was hypoplasic and contained three types of abnormalities, at least: abundant paradentate matrix cell nests, a large mass of @entity76 along the ventral wall of the 4th ventricle and, finally, multiple voluminous @entity3664 (possibly, Purkinje cells) in the subcortical white matter. In addition, there were two small olivary @entity3664 . The correct identification of all @entity154 has been possible for having employed the method of whole brain serial sectioning. We have correlated such cortical, cerebellar and truncal abnormalities to those encountered in similar conditions as lissencephaly, @entity10579 and chromosomal trisomies. The pathogenetic mechanisms triggered by the absence of an X chromosome can affect the neuronal migration, but only after the cortical hemispheric one has been almost completely ended. This could explain why cerebellar and olivary neuronal migration are exclusively affected, being there the migration process chronologically slowed down during the normal neurogenesis. There means we might date after the 4th fetal months the neuronal migration trouble. Finally, we would suggest the soft cortical changes in such crucial regions as the frontal and hippocampal cortex to be possibly responsible for the degree of @entity1032 seen in these @entity1 .(ABSTRACT TRUNCATED AT 250 WORDS)
