[Sib cases of Dandy-Walker syndrome (author's transl)].

Two children of normal parents had "Dandy-Walker syndrome" (cystic dilatation of the 4th ventricle with incomplete development of the cerebeller vermis). Both cases were admitted to our hospital in neonatal period, because of apneic spell. Air study showed the enlargement of the 4th ventricle in both cases. One case (22 days after birth, male infant) was operated by occipital craniotomy, and cystic membrane of the roof of the 4th ventricle was removed. But his head was growing rapidly in size, which suggested hydrocephalus. He died of pneumonia at 70 days after V-P shunt operation. At autopsy, defect of the cerebellar vermis and tonsil, involving the enlargement of the 4th ventricle was found. Another case, younger sister of the previous one, was complicated by occipital meningocele, which did not communicated with ventricular system. Her occipital tumor was removed, and now, she is growing normally in body size, but does not react to the visual stimuli with considerable psychomotor retardation. In our cases, occlusion of the foramina Luschka and Magendie was not present. So, we have come to the conclusion that primary underdevelopment of the cerebellum is of major importance for understanding of the etiopathogenesis of this syndrome.