Structural Anomalies in the Cerebellum in Association With Trisomy

The medical literature on chromosomal aberrations, and their relation to phenotypic abnormalities in outer form and inner organ systems has steadily increased during recent years. In reflecting on the wide spectrum of these abnormal structural changes, and on some recent attempts at their interpretation in terms of specific autosomal deviations, the need for more detailed histological analysis is apparent, in particular with regard to the central nervous system (CNS). Abnormal microscopic findings in organs which appear normal grossly, such as the kidney, pancreas, and adrenal glands have been recently reported in cases of trisomia. 1 It was to be expected that a microscopic study of the CNS by the conventional celloidin technique on large sections would yield findings which might be missed in the smaller sections from paraffin blocks as customarily prepared in the tissue laboratories of pathologists. Whereas such striking anomalies as the absence of olfactory nerves and tracts,