GSTM1 and Priapism: In contrast, HC treatment in the priapism group seemed to lead to a substantial increase of not only MCV (81.4 ± 4.9 vs 101fl ± 11.6, p = 0.0002) but also HbF expression (3.5 ± 1.35 vs 12.3% ±5.3, p = 0.0004) and Hb level (7.1 ± 1.2 vs 8.8g/dl ± 1.1, p = 0.0005).