DCX and hypothyroidism: In summary, we used two rat models to show that developmental iodine-deficiency and hypothyroidism causes irreversible mal-regulation of doublecortin and NCAM-180 a few weeks before the obvious injury of nerve fibers in the hippocampus, demonstrating that the developmental iodine deficiency and hypothyroidism impair the expression of doublecortin and NCAM-180, leading to nerve fiber malfunction and thus the impairment in hippocampal development.