Doublecortin was originally discovered since defects in the gene encoding it are causative of an X-linked lissencephaly, a rare group of brain malformations resulting in a smooth cerebral cortex caused by aberrant neuronal migration during development. The name doublecortin comes from the unusual layering of the cortex in this form of lissencephaly, which appears to have a second deep cortical layer of neurons. The doublecortin protein appears to function as a microtubule and actin binding protein expressed in developing neuroblasts as they become post-mitotic, but is lost as neurons mature. Loss of doublecortin causes defects in neuronal migration during development, so that many neurons fail to migrate into the cortex but remain close to the ventricular germinal zones. Antibodies to doublecortin are useful to identify neuronal stem cells and developing neurons in sections and in tissue culture, and to monitor neurogenesis. Studies of neuroblastoma, the most common form of extracranial solid tumor in childhood, show that levels of doublecortin mRNA are associated with poor patient outcome . The Doublecortin antibody was made against full length recombinant human doublecortin expressed in and purified from E. coli.