The notion of interrelated peroxisomal processes of biogenesis and metabolism may also yield mechanistic insight into therapeutic intervention in peroxisomal biogenesis disorders, where pharmacological treatment with 4-phenylbutyrate concomitantly induced PEX11A dependent peroxisomal proliferation and ABCD2 mediated peroxisomal transport of fatty acids (Kemp et al., 1998; Wei et al., 2000). The gene discussed is ABCD2; the disease is peroxisomal disease.