According to the results of the largest adult cohort, MBL deficiency is not correlated with more frequent or more prolonged febrile episodes during myelosuppressive chemotherapy in adults with hematological cancer, but severe infections are more frequent in MBL-deficient patients and first severe infection develops earlier in this group compared with nondeficient patients [8]. The gene discussed is MBL2; the disease is hyperinsulinemic hypoglycemia, familial, 4.