The similarities between primary IgAN and HSP-IgAN have been stressed since a long time, but recently the common pathogenesis was demonstrated [25,26] with data on the autoantigen, galactose-deficient IgA1, and specific autoantibodies (IgG and IgA subclasses); a common genetic background for this galactose-deficient IgA1 was also described [27]. The gene discussed is CD79A; the disease is hereditary spastic paraplegia.