Lissencephaly: two distinct clinico-pathological types.

The present study is a review of four new cases of lissencephaly and two others previously reported. This study demonstrates that lissencephaly is a gross feature of the brain occurring in two different groups of cortical malformations. The first group, the classic agyria syndrome extensively analyzed by Jellinger and Rett [8] includes two types of abnormal cortical organization. They may be found in familial syndromes and also can appear sporadically. The second group includes smooth brains with the internal features of polymicrogyria and a more severely disorganized cortex. This type appears in familial lissencephaly in the cerebro-oculo-muscular syndrome, belonging to the same group as Fukuyama congenital-cerebro-muscular dystrophy. The other incidences of this type of cortical malformation require further investigation. The clinico-pathological differential diagnosis of two types of lissencephaly are also discussed.