Glycogen storage disease type 1B
Overview
Glycogen storage disease type 1b (medical condition): A metabolic disorder involving a deficiency of glucose-6-phosphatase (due to a G6P transporter defect) which results in the accumulation of glycogen in various tissues and a reduced blood sugar level. The condition is characterized primarily by an increased risk of bacterial infections due to impaired neutrophil activity which is needed to fight bacterial invasions.
Symptoms
Some of the symptoms of Glycogen storage disease type 1b incude: * Protruding abromen * Diarrhea * Growth failure * Enlarged liver * Yellowish red spots on legs
Causes
* GSD Ia and Ib are autosomal recessive genetic traits caused by mutations at loci 17q21 and 11q23, respectively. * GSD Ia is caused by deficient activity of the enzyme glucose-6-phosphatase, representing at least 14 distinct allelic variants. * GSD Ib is caused by deficiency of glucose-6-phosphate translocase, which is responsible for importing glucose-6-phosphate from the cytosol to the interior of the microsome, thus bringing substrate into contact with enzyme. To date, allelic variation in this disorder has not been explored.
Diagnosis
Diagnosis depends on muscle biopsy, electromyelography, ischemic forearm test, creatine kinase levels, patient history, and physical examination. Biochemical assay for enzyme activity is the method of definitive diagnosis.