GSTM1 and glycogen storage disease VI: Hb electrophoresis revealed reduced Hb A and Hb E, with small amounts of Hb Bart’s and Hb H. The lower affinity of alpha globin chains for beta E-globin chains compared to beta A-globin chains leads to decreased Hb E levels (13-15%), differentiating it from classic Hb H disease [9].