Related Experiment Video
Updated: Aug 13, 2026
07:16
Biochemical Titration of Glycogen In vitro
Published on: November 25, 2013
Glycogen storage disease type Ib without neutropenia
1Department of Medical Genetics, Tohoku University School of Medicine, Sendai, Japan.
The Journal of Pediatrics
|August 10, 2000
Summary
Two patients with atypical glycogen storage disease type Ib, lacking neutropenia and infections, were identified. Both had mutations in the glucose-6-phosphate transporter gene, indicating a variant form of this metabolic disorder.
Area of Science:
- Biochemistry
- Genetics
- Pediatric Endocrinology
Background:
- Glycogen storage disease type Ib (GSD Ib) is a rare metabolic disorder.
- It typically presents with neutropenia, recurrent infections, and impaired hepatic glucose production.
- Genetic mutations in the glucose-6-phosphate transporter gene (SLC37A4) are the underlying cause.
Observation:
- Two pediatric patients presented with clinical and biochemical features suggestive of GSD Ib.
- However, these patients lacked the characteristic neutropenia and infectious complications.
- Hepatic glucose-6-phosphatase activities were not deficient in microsome-disrupted homogenates.
Findings:
- Both patients harbored mutations in the glucose-6-phosphate transporter gene (SLC37A4).
- The absence of neutropenia and infections suggests an atypical or allelic variant of GSD Ib.
- This finding challenges the typical presentation and diagnostic criteria for GSD Ib.
Implications:
- These cases expand the phenotypic spectrum of glycogen storage disease type Ib.
- It highlights the importance of genetic testing for SLC37A4 mutations in suspected GSD Ib cases, even without classic symptoms.
- Further research is needed to understand the molecular mechanisms underlying this atypical presentation and its long-term outcomes.
More Related Videos
Related Concept Videos
01:22Lysosomal Hydrolases
Lysosomes are the site for the degradation of macromolecules and biological polymers released during membrane trafficking events such as secretory, endocytic, autophagic, and phagocytic pathways. The membrane-enclosed area of the lysosome, called the lumen, contains hydrolytic enzymes active in an acidic environment. These acid hydrolases are functional at a pH between 4.5 and 5 and are involved in cellular processes such as cell signaling, energy metabolism, restoration of the plasma membrane,...
01:22Diabetes Mellitus: Overview and Type I Subtype
Diabetes mellitus is a chronic metabolic disorder characterized by high blood glucose levels due to inadequate insulin production, insulin resistance, or both. The condition affects millions worldwide and can significantly impact their health and quality of life.
Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. As a result, the body is unable to produce sufficient insulin, and individuals with...
Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. As a result, the body is unable to produce sufficient insulin, and individuals with...
01:20Inborn Errors of Metabolism
Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
01:12Type I Diabetes I: Introduction
Type 1 diabetes mellitus is a chronic metabolic disorder characterized by an absolute deficiency of insulin resulting from the autoimmune destruction of pancreatic β-cells. Although it can occur at any age, it is most commonly diagnosed in childhood, adolescence, or early adulthood. The loss of insulin production impairs cellular glucose uptake, resulting in persistent hyperglycemia and necessitating lifelong insulin therapy.Autoimmune Destruction of β-CellsThe hallmark of type 1 diabetes is an...
01:26Type I Diabetes II: Pathophysiology
Type 1 diabetes mellitus arises from an immune-mediated destruction of pancreatic β-cells, resulting in an absolute deficiency of insulin. This process develops in genetically susceptible individuals when autoimmunity, environmental exposures, and immunologic dysregulation converge to trigger a targeted attack on the insulin-producing cells of the pancreas. The β-cells are located within the islets of Langerhans and are essential for regulating blood glucose by facilitating cellular uptake of...
01:19Type I Diabetes III: Clinical Manifestations
Type 1 diabetes mellitus typically presents with rapid-onset symptoms due to the body’s inability to utilize glucose in the absence of insulin. Since insulin is required for glucose uptake into cells, its deficiency leads to hyperglycemia and cellular energy deprivation, resulting in characteristic clinical features.Polyuria and PolydipsiaOne of the earliest, most prominent symptoms is polyuria (excessive urination). When blood glucose concentrations rise above the renal threshold, the kidneys...