Because the Ikbkap gene is broadly expressed throughout the nervous system in both mice and humans (Mezey et al., 2003), and our Ta1-cre was active in many neuronal populations outside of the retina in both the central and peripheral nervous system (Chaverra et al., unpublished observations), we cannot conclude whether the RGC deficits observed in both FD patients and this mouse model were due to direct or indirect consequences of Ikbkap loss in the retina. The gene discussed is ELP1; the disease is Fabry disease.