Glycogen Storage Disease Ib

A number sign (#) is used with this entry because of evidence that type Ib glycogen storage disease (GSD1B) is caused by homozygous or compound heterozygous mutation in the G6PT1 gene (SLC37A4; 602671), which encodes glucose-6-phosphate translocase, on chromosome 11q23.

Senior and Loridan (1968) proposed the existence of a second type of von Gierke disease in which, although glucose-6-phosphatase (G6PC; 613742) activity is present on in vitro assay, glucose is not liberated from glucose-6-phosphate in vivo. They referred to this as 'functional deficiency of G6P.' They pointed out that some mutants in Neurospora show impaired enzyme function in the intact fungus despite normal activity in homogenates.

Arion et al. (1975) concluded that G6Pase activity requires 2 components of the microsomal membrane: (1) a glucose-6-phosphate specific transport system that shuttles G6P from the cytoplasm to the lumen of the endoplasmic reticulum (a G6P translocase), and (2) an enzyme, glucose-6-phosphate phosphohydrolase, bound to the luminal surface of the membrane.

Narisawa et al. (1978) described a patient who appeared to have a defect in the transport system. In liver without detergent, enzyme activity was very low but normal activity was obtained by addition of detergent. Kuzuya et al. (1983) reported a 25-year-old patient. Protuberant abdomen and diarrhea were noted at age 1 or 2 years, and short stature and hepatomegaly at age 4 years. At age 18, yellowish-red spots appeared on her legs and hypertension was detected. At age 20, she was 138 cm tall. Eruptive xanthoma and hyperlipidemia were present. Liver scintigraphy suggested the presence of adenomas.

Recurrent infections and neutropenia have been recognized as distinctive features of GSD Ib. Corbeel et al. (1983) provided a 6-year follow-up on the hematologic effects of termino-lateral portacaval anastomosis. Granulocyte counts returned to normal and recurrent infections ceased after the shunt. Platelet dysfunction, evident before surgery, was also corrected. Marked hypochromic anemia, probably caused by sequestration of iron in the spleen and resistant to therapy, was a persistent feature in this patient. The mechanism of the granulocyte defect in this disorder was discussed. Roe et al. (1986) observed Crohn disease in 2 unrelated boys with GSD Ib. Their neutrophils showed severe chronic neutropenia and markedly deficient chemotactic response, whereas the leukocytes were normal in 4 patients with GSD Ia (232200). Thus, chronic inflammatory bowel disease (IBD; see 266600) appears to be an integral part of GSD Ib and the abnormality of leukocytes is probably involved in the pathogenesis of the IBD. Oral lesions and perianal abscesses are common in this disorder (Ambruso et al., 1985). Ueno et al. (1986) found that neutrophils were defective in both motility and respiratory burst, whereas monocytes showed a defect only in respiratory burst. Bashan et al. (1988) showed that the rate of 2-deoxyglucose transport into GSD Ib polymorphonuclear leukocytes was 30% of that into cells of normal controls. Transport was normal in GSD Ib lymphocytes and in GSD Ia polymorphonuclear leukocytes and lymphocytes. The striking limitation of glucose transport across the cell membrane of polymorphonuclear leukocytes probably accounts for the impairment of leukocyte function that is characteristic of GSD Ib but not GSD Ia. Schroten et al. (1991) used granulocyte colony-stimulating factor (CSF3; 138970) to treat successfully the neutropenia in 2 patients with GSD Ib associated with recurrent bacterial infections. Roe et al. (1992) administered granulocyte-macrophage colony stimulating factor (CSF2; 138960) to the 2 adolescent boys whom they had reported in 1986 (Roe et al., 1986). They observed a prompt increase in neutrophil counts to normal, complete relief from abdominal symptoms, and an increase in appetite, energy, and weight, and a feeling of well being. There was radiologic evidence of bowel healing and a decrease in the erythrocyte sedimentation rate. Both patients remained free of oral and anal lesions over a period of 10 and 12 months of treatment. One patient was switched to G-CSF (CSF3) because of a presumed allergic reaction to GM-CSF. In a multicenter study in the United States and Canada, Talente et al. (1994) identified 5 patients with GSD type Ib who were 18 years of age or older. Severe recurrent bacterial infections and gingivitis were present. One patient, a 22-year-old college student, was described in detail. She had severe recurrent stomatitis, recurrent otitis media and externa, perianal and perirectal abscesses, and, at the age of 12 years, 2 brain abscesses due to Staphylococcus aureus. At 18 years of age, she was as tall as an 8-year-old and had not undergone any pubertal changes.

In a patient with GSD Ib, Heyne and Henke-Wolter (1989) found a change in the oligosaccharide side chains of the alpha-1-antitrypsin (107400) glycoprotein suggesting effects of the limited availability of glucose or glucose derivatives for the synthesis of N-glycosidic glycoproteins. Kikuchi et al. (1990) found secondary amyloidosis in a 12-year-old girl with GSD Ib.

In 14 children (aged 4 to 16 years) with GSD Ia and GSD Ib, Lee et al. (1996) found that the use of uncooked cornstarch loads resulted in satisfactory glycemia lasting only a median of 4.25 hours (range 2.5 to 6).

In studies of 5 patients with GSD Ib, Kuijpers et al. (2003) found neutrophils in the circulation that showed signs of apoptosis with increased caspase activity, condensed nuclei, and perinuclear clustering of mitochondria to which the proapoptotic BCL2 member BAX (600040) had translocated already. Granulocyte colony-stimulating factor (GCSF; 138970) added to in vitro cultures did not rescue the GSD Ib neutrophils from apoptosis as occurred with GCSF-treated control neutrophils. Moreover, the 2 GSD Ib patients on GCSF treatment did not show significantly lower levels of apoptotic neutrophils in the bloodstream. Kuijpers et al. (2003) studied neutrophils from children with infections (active pneumonia or septicemia) or with other neutropenic syndromes (Shwachman-Diamond syndrome; 260400), but to date had not observed circulating apoptotic neutrophils in these patients.

Annabi et al. (1998) reported linkage of the GSD Ib locus to genetic markers spanning a 3-cM region on 11q23. The region is located between D11S939 centromerically and D11S4129 telomerically and includes the IL10R (146933), ATP1G1 (601814), and ALL1 (159555) genes. The authors studied 8 consanguineous families and 1 nonconsanguineous family of various ethnic origins. The assignment to chromosome 11 was confirmed by Kure et al. (1998), who showed that the translocase gene that is mutated in this disorder maps to chromosome 11 by study of somatic cell hybrids.

In 2 female patients with GSD Ib, Gerin et al. (1997) found 2 point mutations in the glucose-6-phosphate translocase gene (602671.0001 and 602671.0002). Kure et al. (1998) identified 3 additional mutations, one of which, W118R (602671.0003), may be unusually frequent among Japanese patients with GSD Ib.

Kure et al. (2000) proposed that GSD Ib without neutropenia could be due to glucose-6-phosphate translocase mutations with residual transporter activity based on finding biallelic mutations with normal liver microsomal GTPase activity in 2 Japanese patients; see 602671.0015 and 602671.0016.

Chou and Mansfield (1999) reviewed the molecular genetics of type I glycogen storage diseases.