Septo-optic dysplasia (de Morsier's syndrome) associated with total callosal absence. A new type of the anomaly.

It is currently believed that there are two subsets of septo-optic dysplasia (de Morsier's syndrome), one with schizencephaly and the other without schizencephaly. Also, some authors consider septo-optic dysplasia as a mild form of holo-prosencephaly. This article describes a third form of the anomaly which is associated with total callosal absence. Two patients similar to this one have previously been reported. None of these three patients had interhemispheric fusion in any form, excluding holoprosencephaly. They had normal facies. All of them presented with seizures, and no hormonal abnormality was found. This new clinicoradiological type of the anomaly is suggested to be labelled as calloso-septo-optic or calloso-optic dysplasia.