Sometimes referred to as Type II lissencephaly, cobblestone lissencephaly is also caused by abnormalities in the way neurons move. Unlike classical lissencephaly where neurons do not migrate far enough, in cobblestone lissencephaly they migrate too far, forming a bumpy cobblestone surface. The cobblestone lissencephalies fall into three categories: (1) Fukuyama Congenital Muscular Dystrophy; (2) Finnish muscle eye brain disorder; and (3) Walker Warburg syndrome.
Each has its own unique set of symptoms, but most individuals present with muscular and eye abnormalities as well as the characteristic cobblestone cortex. Four genes have been implicated in these syndromes: Walker Warburg syndrome is caused by mutations in POMT1 and POMT2, Finnish muscle eye brain disorder by mutations in POMGnT1, and Fukuyama Congenital Muscular Dystrophy by mutations in fukutin.