Despite recent advances, there is still much to be learned about the pathogenesis of Fabry disease. The categorization of GLA gene missense mutations has been complicated by the fact that some missense variants may fall into more than one category. For instance, the A143T variant may cause late-onset Fabry disease in some subjects and not result in Fabry disease in others (pseudo-deficient). Efforts to mitigate the pathobiology of α-galactosidase A deficiency should differentiate between...