Aiming to gain insights into the mechanisms of neuronal differentiation, we describe the first differential expression profiles of purified homogenous neural precursors (CD133+ cells from human fetal brain) with those of differentiated neurons from human fetal brain. The purity of the two populations of cells was verified by flow cytometry and immunocytochemistry, and cells were then processed for DNA microarray analysis. We confirmed the expression of several previously reported genes (e.g. cell cycle-, DNA replication- and apoptosis-related genes). In addition, we identified, and confirmed by reverse transcription-polymerase chain reaction and in situ hybridization, significant differential expression of platelet-derived growth factor receptor-alpha and insulin-like growth factor binding protein 4, indicating these factors as potential pro-neuronal differentiation factors. In summary, by using the microarray technique to perform a comparative analysis of the genes involved in the differentiation of neural precursors, enriched from the human fetus, we have identified hitherto unknown candidate genes and related signaling pathways that might play an essential role in neuronal differentiation.