This reminiscent of the phenotypes with a high incidence of lumbar spina bifida in the mouse model crossed of un mutant and Patch (Ph) mutant mice (Helwig et al., 1995) which is a deletion of the gene encoding the platelet-derived growth factor receptor alpha subunit (PDGFRα) (Stephenson et al., 1991), suggesting the possibility of an involvement of PAX1 in the occurrence of NTD. The gene discussed is PDGFRA; the disease is neural tube defect.