In addition, since Sema3A can directly induce neurodegeneration and apoptosis of neural progenitor cells (Bagnard et al., 2001), sensory neurons (Gagliardini and Fankhauser, 1999), cerebellar granule cells and sympathetic neurons in vitro (Shirvan et al., 1999, 2000), it may play a direct role in neurodegeneration in AD. The gene discussed is SEMA3A; the disease is Alzheimer disease.