Neutropenia in type IB glycogen storage disease

Defective neutrophil and monocyte functions in glycogen storage disease type Ib: a literature review

A summary review of leukocyte function in 42 published cases of glycogen storage disease Ib is presented. Polymorphonuclear and monocyte dysfunctions were evidenced in the majority of cases, whereas lymphocytes appeared to be unaffected. Phagocyte dysfunctions comprised in vivo mobilization and motility, in vitro random and directed migration, and one or several component functions of the "metabolic" ("respiratory") burst. On the basis of the available data it is impossible to know whether a primary functional deficit of the glucose 6-phosphate transport protein of the microsomal glucose 6-phosphatase system, as demonstrated in liver, also exists in these phagocytic cells and is responsible for this dysfunction.

Glycogen storage disease type IB: a new model of genetic disorders involving the transport system of intracellular membrane

Our studies have revealed that the primary lesion of GSD type Ib exists in the G6P transport system in the microsomal membrane. Distinct evidence for the existence of a specific G6P transport system in microsomal membrane was obtained through these studies. This is the first example of a genetic disorder involving the transport system of an intracellular membrane. HHH syndrome (hyperornithinemia, hyperammonemia, and homocitrullinuria), in which the transport of ornithine to the mitochondria is presumed to be defective, may be another example belonging to this category of genetic disorders (18-20). A possibility exists that there are many other disorders due to defects in the membrane transport of intracellular organelles.

Glycogen storage disease type Ib

Glycogen storage disease type Ib has all the clinical manifestations of glycogen storage disease type Ia such as hepatomegaly, growth retardation, bleeding tendency, hypoglycemia, hyperlactacidemia, hyperuricemia, hyperlipidemia, impaired platelet function plus neutropenia. The overall glucose-6-phosphatase activity in disrupted microsomes from liver is normal whereas glucose-6-phosphate translocase, the first enzyme in the glucose-6-phosphate transport system is absent. There is no glucose-6-phosphatase activity in vivo. Recent results show that in granulocytes the glucose-6-phosphate-dependent hexosemonophosphate-shunt is impaired.