Severe congenital neutropenia type 4 (SCN4, OMIM# 612541) is caused by autosomal recessive mutations in G6PC3 on 17q21.31, which encodes one of the three subunits of the enzyme glucose-6-phosphatase. Here, G6PC3 is linked to autosomal recessive severe congenital neutropenia due to G6PC3 deficiency.