SLC37A4 and neutropenia: Regarding neutropenia in GSDIb, which involves mutations in the glucose-6-phosphate translocase (G6PT), Veiga da Cunha et al. [49] proved recently that it is caused by excessive accumulation of a nonclassical metabolite with unknown physiological role, 1,5-anhydroglucitol-6-phosphate (1,5AG6P), which results from the phosphorylation of 1,5-anhydroglucitol (1,5AG), also called 1-deoxyglucose, a glucose analog normally present in blood.