Quantitative RT-PCR of STEAP3/TSAP6 mRNA from blood cells. The results of STEAP3/TSAP6 mRNA quantification are expressed in arbitrary units as the ratio of STEAP3/TSAP6 mRNA to B2M mRNA (STEAP3/B2M). Quantitative PCR was carried out for each cDNA sample, and the ratios of STEAP3 to the control gene B2M were calculated as the mean of triplicate determinations. A wide range of variation for 10 normal control subjects was observed (3-fold) and both parents were in the lower range of the controls. Note that in the father and in his 3 affected children, only the normal allele was detected by sequencing of RT-PCR products because of degradation of the mutated allele (Figure 2B).