GSTM1 and glycogen storage disease VI: In contrast to the report of Chen et al. which found that the G-Taichung variant would aggravate the clinical symptoms in patients with Hb H disease [18], the 8 patients with (–/-α4.2  G-Taichung) genotype in this study were clinically similar to those with deletional Hb H disease, such as (–/-α3.7) or (–/-α4.2) genotypes.