Since there are multiple forms of lissencephaly, I would like to make some consideration regarding its classification.
Two large groups can be distinguished: classical lissencephaly or type I (and its variants) and cobblestone lissencephaly or type II. Type I lissencephaly is associated with specific craniofacial findings and characteristic pathological changes (microcephaly and a thickened cortex with four, rather than six, layers). It is a major manifestation of Miller-Dieker and Norman-Roberts syndromes, but also occurs as an isolated developmental defect. Type II lissencephaly is associated with obstructive ventriculomegaly and with other severe malformations of the brain, in addition to being affected other organs such as eyes and muscles. The surface of the brain is predominantly agyric with a somewhat verrucous appearance, hence the name "cobblestone lissencephaly". It is classified into three different conditions: Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama congenital muscular dystrophy.
Some forms of lissencephaly do not fall into either of these two categories, which leads us to speak of type III smooth brain. Type III lissencephaly is characterized by a severe microcephaly, agyria, agenesis of the corpus callosum and hypoplasia of the cerebellum and the nuclei of the base. It occurs in three recessive syndromes: Neu-Laxova syndrome, Lissencephaly Encha-Razavi-Larroche type and the syndrome reported by Plauchu (with microcephaly, agenesis of the corpus callosum, cerebellar hypoplasia, dysmorphia and punctuated epiphyses).
In the present case we can assume that we are dealing with one of the many diseases of type I lissencephaly, because of the presence of hypertelorism and flat profile in addition to lissencephaly (clearly demonstrated by the flattening and morphology of the Sylvian fissure). Another data that supports this conclusion is the absence of ventriculomegaly, highly prevalent in cases of type II lissencephaly.
Two large groups can be distinguished: classical lissencephaly or type I (and its variants) and cobblestone lissencephaly or type II. Type I lissencephaly is associated with specific craniofacial findings and characteristic pathological changes (microcephaly and a thickened cortex with four, rather than six, layers). It is a major manifestation of Miller-Dieker and Norman-Roberts syndromes, but also occurs as an isolated developmental defect. Type II lissencephaly is associated with obstructive ventriculomegaly and with other severe malformations of the brain, in addition to being affected other organs such as eyes and muscles. The surface of the brain is predominantly agyric with a somewhat verrucous appearance, hence the name "cobblestone lissencephaly". It is classified into three different conditions: Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama congenital muscular dystrophy.
Some forms of lissencephaly do not fall into either of these two categories, which leads us to speak of type III smooth brain. Type III lissencephaly is characterized by a severe microcephaly, agyria, agenesis of the corpus callosum and hypoplasia of the cerebellum and the nuclei of the base. It occurs in three recessive syndromes: Neu-Laxova syndrome, Lissencephaly Encha-Razavi-Larroche type and the syndrome reported by Plauchu (with microcephaly, agenesis of the corpus callosum, cerebellar hypoplasia, dysmorphia and punctuated epiphyses).
In the present case we can assume that we are dealing with one of the many diseases of type I lissencephaly, because of the presence of hypertelorism and flat profile in addition to lissencephaly (clearly demonstrated by the flattening and morphology of the Sylvian fissure). Another data that supports this conclusion is the absence of ventriculomegaly, highly prevalent in cases of type II lissencephaly.