Neutropenia is an essential finding in GSD-Ib and GSD-associated IBD; in addition to diet management and cornstarch maintenance of blood glucose, 5-aminosalicylic acid and granulocyte-colony stimulating factor (G-CSF) are commonly used for the management of neutropenia-induced infections and colitis in patients with GSD-Ib10,14,15. Here, CSF3 is linked to neutropenia.