A Golgi study of cerebellar malformation in 13 trisomy.

The structure of cerebellar malformations in the brains of two infants with 13 trisomy has been studied by means of the Golgi method. Poorly organized cerebellar dysplasias (heterotaxias) are composed of Purkinje, Golgi and granule cells arranged and oriented in a disorderly fashion. The variable orientation and organization of the dendritic arbor of Purkinje cells within these cellular aggregates is supposed to be related to abnormal distribution of parallel fibers. Large ganglion cell heterotopias are not a homogeneous group, but two distinct types may be defined. First, Purkinje cell heterotopias which are located in the white matter of the cerebellum below the normally formed folia; these are composed of large neurons with arrested migration to the cortex. Secondly, multipolar cell heterotopias which are located in the deep white matter near the dentate and the roof nuclei, formed of neurons belonging to the deep cerebellar nuclei.