Abnormal expression of cell adhesion molecule L1 in migration disorders: a developmental immunohistochemical study.

We studied immunohistochemically the expression pattern of a neural cell adhesion molecule, L1, in various human migration disorders associated with polymicrogyria: 4 fetuses and 11 infants having Fukuyama type congenital muscular dystrophy (FCMD) (4 cases), Zellweger syndrome (6) or thanatophoric dysplasia (3) and intrauterine brain damages (2) at different development stages, comparing to age-matched controls. There were different patterns of L1 expression, which suggested at least 3 pathogenetic mechanisms: high expression associated with neuoraxonal overgrowth (fetal FCMD and destructive event at intermigratory period); delayed expression with neuronal dysmaturation and dysmyelinogenesis (late infantile stage of Zellweger syndrome); no expression in toxic or destructive brain injury (Zellweger syndrome or destructive events at inter-or postmigratory periods).