Minet et al. (1999) reported that culture substrate coated with the YD repeat region of chicken teneurin-1 supported neuron outgrowth from dorsal root ganglion explants. Therefore, defects in YD repeats might contribute to development of psychiatric diseases due to its role in neuron development. And our results thus warranted further studies of the YD repeats and TENM4 in molecular mechanism of schizophrenia. The gene discussed is TENM4; the disease is psychiatric disorder.