Structural anomalies in the cerebellum in association with trisomy

Publisher Website
Google Scholar
Abstract
Anomalous structures in the cerebellum, including dysplastic and dystopic gyri, heterotopias of neurons and undifferentiated cells in the white matter, in some roof nuclei, the ventral cochlear nuclei, and especially in the dentate nuclei, were observed in 5 cases of trisomy 13-15 syndrome (trisomy D). All of these had characteristic phenotypic abnormalities of the eyes and optic nerves or of olfactory nerves and various inner organ systems. The undifferentiated cells in the dentates, roof nuclei, and in the white matter seemed to stem from the embryonal external granular layer of the cerebellar cortex. Three cases of trisomy 13-15 syndrome had the characteristic karyotype with 47 chromosomes, the other 2 represented D-D fusion and C-D translocation. Similar anomalies in the cerebellum were present also in 3 infants with mon-golism, and in 19 newborns and young infants with a variety of associated malformations of the phenotype of trisomy 13-15 syndrome. In none of these observed during previous years were chromosomal studies available. In 3 of 5 cases of trisomy 18 syndrome (trisomy E), with the characteristic karyotype and phenotype, there were only minor anomalies in the cerebellum, especially in some roof nuclei and in a few folia close to the vermis. These restricted anomalies were also observed in cerebellar sections of newborns and infants in the absence of malformations or anomalies in any other organ. From the recent literature on more complex malformations of the entire CNS, it is apparent that their association with malformations of the trisomy 13-15 phenotype can occur in the absence of chromosomal abnormalities. Similar experiences from the laboratory suggest that phenotypically similar abnormalities, especially of the CNS, can be divided into 2 groups: true hereditary abnormalities which occur in patients with a normal karyotype and in several siblings of the same parent, and abnormalities which occur in patients with proved karyotype D or E and have thus far been observed only in one sibling of the same parents.