But with advances in molecular genetic methods, the patients with GSD IaSP have discovered to have mutations in G6PC and most patients with GSD Ic and Id have mutations in the G6PT1 gene SLC37A4, therefore GSD I is now divided into two general subtypes GSD Ia and GSD I non-a, respectively (Lei et al., 1995[31]; Veiga-Da-Cunha et al., 1999[57]). The gene discussed is SLC37A4; the disease is glycogen storage disease Ib.