G6PC3 deficiency is characterized by extreme congenital neutropenia that occurs in a phenotypic spectrum from (a) Isolated severe congenital neutropenia (non-syndromic) to (b) Classic G6PC3 deficiency (syndromic), which is severe congenital neutropenia plus cardiovascular and/or urogenital abnormalities [8]. The gene discussed is G6PC3; the disease is neutropenia.