Since gene expression quantification using RT-qPCR requires a steady reference gene, we selected three genes frequently used for normalization of the data, ABL1, RPLP0, and HPRT1. We confirmed that PMEPA1 (Figure 4A), the most dysregulated gene on the microarray, and S100A16 (Figure 4B), were significantly underexpressed in FD samples. The gene discussed is HPRT1; the disease is Fabry disease.