Isolated absence of the septum pellucidum

Absence of the septum pellucidum in the human is a rare congenital anomaly. Previous re:ports suggest it is almost always associated with other brain anomalies. However, MRI in two patients with absence of the septum pellucid um presented here, indicates that this anomaly may occur without associated anomalies. It may be one manifestation of a spectrum of developmental anom alies. One patient presented with schizophrenic psychosis; developmental di sturbances in limbic areas are believed to be associated with schizophrenia . Agenesis of the septum pellucidum may indicate abnormal development of li mbic structures and it may be associated with anomalies, such as cytoarchit ectural disturbances of cortical layers, as yet undetectable by MRI.