ADHESION MOLECULES AND INHERITED DISEASES OF THE HUMAN NERVOUS-SYSTEM

Mutations in the human genes for the adhesion molecules Po, L1, and me rosin cause severe abnormalities in nervous system development. Po and merosin are required for normal myelination in the nervous system, an d L1 is essential for development of major axon pathways such as the c orticospinal tract and corpus callosum. While mutations that lead to a loss of the adhesive function of these molecules produce severe pheno types, mutations that disrupt intracellular signals or intracellular i nteractions are also deleterious. Geneticists have found that more tha n one clinical syndrome can be caused by mutations in each of these ad hesion molecules, confirming that these proteins are multifunctional. This review focuses on identifying common mechanisms by which mutation s in adhesion molecules alter neural development.