"Some authors do not use the term schizencephaly, preferring to group these disorders under the blanket term of porencephaly. For the purpose of this article, and generally speaking, schizencephaly is reserved for clefts lined by grey matter (polymicrogyria) thought to represent a true malformation, whereas porencephaly implies an encephaloclastic event (e.g. ischaemia)."
"Schizencephaly is rare with an estimated incidence of ~1.5:100,000 live births. It is almost always sporadic, although a few familial cases have been described 6. There is no known gender predilection 6."