CD79A and hereditary spastic paraplegia: Previous reports have already demonstrated that HSP patients present with a high serum IgA concentration (Saulsbury 1999; Calvino et al. 2001; Trapani et al. 2005), low C3 or C4 (Calvino et al. 2001; Trapani et al. 2005), and leukocytosis (Trapani et al. 2005).