G6PD and hyperinsulinemic hypoglycemia, familial, 4: The mutation causing G6PD deficiency reduces the enzymatic activity in all tissues equally; however, in the case of the Mediterranean variant (S188F), the mutation makes the protein unstable; although, the short half-life of leukocytes (1–2 days) and their ability to synthesize proteins, can maintain reasonably high levels of G6PD [79].