Coexistence of several developmental abnormalities in adults is very rare and often asymptomatic. In many instances appearance of clinical symptomatology is evoked by some additional factors, not related directly with the basic pathological process. In a 21-year-old oligophrenic man a progressive paresis of inferior limbs appeared in the course of the upper respiratory tract infection. During 5 days of hospitalization transient peripheral paresis of the right facial nerve, tetraplegia, sphincter and respiratory disturbances occurred. Guillain-Barré syndrome and subarachnoid hemorrhage were diagnosed. On autopsy hemorrhagic focus in the medulla and in the cervical and upper thoracic parts of the spinal cord was found. Microscopic examination revealed hypocellularity of the 2nd and 4th layers of the temporal cortex, presence of the central canal within the brain stem, and hemorrhagic focus in the medulla. Two malformations in spinal cord were revealed: intraspinal angioma extending from the C2 to the Th6 segments and diastematomyelia within Th11 and lumbar segments. Diastematomyelia, cortical hypocellularity and angioma composed of fetal, lacunar artery- and vein-like vessels, are related with different periods of the ontogenic development. Coexistence of these malformations indicates prolonged action of the pathogenic factor(s), both in the embryonic and fetal life.