Cobblestone lissencephaly with normal eyes and muscle.

Cobblestone lissencephaly is the characteristic brain malformation observed in Fukuyama congenital muscular dystrophy (FCMD), muscle-eye-brain disease (MEB), and Walker-Warburg syndrome (WWS). The diagnostic criteria for all three require the presence of congenital muscular dystrophy, and criteria for MEB and WWS require retinal abnormalities. We report three patients from two consanguineous families of Middle Eastern origin with cobblestone lissencephaly but no abnormalities of the eyes or muscle. Based on the current diagnostic criteria for the cobblestone lissencephaly syndromes, this disorder must be classified separately from the others, but it may well be allelic to MEB and WWS. Linkage studies have excluded the gene for this disorder from the region of the FCMD gene on chromosome 9q31-32.