Both IgG and IgM antibodies binding to fixed Aa-HSP in neonates and in immunized mice were effectively outcompeted by Aa-HSP, but partially competed by MAA-LDL, implying that the induced antibodies are not ideally bound to MAA-LDL or are less specific to MAA-LDL. This evidence concerns the gene HSP90B2P and hereditary spastic paraplegia.