AbstractA girl had persistent regurgitation of food from the first week of life until death at 19 weeks of age. Postmortem examination revealed widespread congenital anomalies including neuronal and neuroglial heterotopias of the thalamus and centrum semiovale on the left side, subependymal regions of both lateral and third ventricles, and both rostral medullary pyramids; and hy‐poplasia of the thalamus and cerebrum on the left side, and both lenticular nuclei. Moreover, the left lateral ventricle was moderately dilated, secondary to partial occlusion of the ipsilateral interventricular foramen. The left thalamus and hem‐icerebrum, as well as both lenticular nuclei, were remarkably small. The brain‐stem was normal except for pyramidal neuronal and neuroglial heterotopias, a finding not previously reported. The mechanism producing a small left thalamus, lenticular nuclei, and cerebrum on the left side is suggested as a combination of hypoplasia from aberrant migration of neuroepithelial derivations, a dilated left lateral ventricle, and degeneration of connecting nerve fibers. Decrease in size of the right lenticular nucleus is the result of hypoplasia alone. It is proposed that the lesions in the thalamus and cerebrum on the left side were responsible for regurgitation because of imbalanced supranuclear control of intact nuclei in the brai