Spongy encephalopathy in ketotic hyperglycinemia

Three cases of ketotic hyperglycinemia are described. Spongy encephalopathy was present in white as well as gray matter. The cell type that predominantly exhibited swelling was the astrocyte. Glycine binding is required for activation of the NMDA receptor. By constant excitation a surplus of glycine could disturb the ion balance. This might provide the pathogenetic principle of seizures and cytotoxic edema in hyperglycinemia.