Glucose-6-phosphatase 3, also known as glucose-6-phosphatase beta, is an enzyme that in humans is encoded by the G6PC3 gene.
This gene encodes the catalytic subunit of glucose 6-phosphatase (G6Pase). G6Pase is located in the endoplasmic reticulum (ER) and catalyzes the hydrolysis of glucose 6-phosphate to glucose and phosphate in the last step of the gluconeogenic and glycogenolytic pathways.
Mutations in this gene result in autosomal recessive severe congenital neutropenia.
G6PC3 deficiency results in a phenotypic continuum. At one end the affected individuals have only neutropenia and related complications but no other organ is affected. This is sometimes referred to as non-syndromic or isolated severe congenital neutropenia. Most affected individuals have a classic form of the disease with severe congenital neutropenia and cardiovascular and/or urogenital abnormalities. Some individuals have severe G6PC3 deficiency (also known as Dursun syndrome) and they have all the features of classic G6PC3 deficiency but in addition show involvement of non-myeloid hematopoietic cell lines, some other extra-hematologic features and pulmonary hypertension.