[Pathological anatomy of defects of the prosencephalic group]

Morphological changes in the brain were studied in 14 observations of defects of the prosencephalic group. These defects were shown to be of three kinds: prosencephaly, alobar prosencephaly, and holoprosencephaly, and to be due to partial or complete undivision of the cranial part of the medullary tube. The nature of these defects is heterogeneous. Most frequently prosencephalitic defects are due to autosomal aberrrations (trisomy 13 and 18, 13-q-, 18p-, triploidy), and may also be due to gene mutations. In cases of trisomy 13 these defects are regularly accompanied by structural disorders of cytoarchitectonics of the cortex of the end brain, cerebellum, and medulla, which may be important for differential diagnosis of prosencephaly of various etiologies.