Glycogen storage disease (GSD) type IB is an inherited disorder that is associated with the accumulation of glycogen in the body's cells. This accumulation in different parts of the body impairs their ability to function normally. Patients present with neutropenia, inflammatory bowel disease, oral problems, hepatomegaly, hypoglycemia, lactic acidosis, hyperuricemia, and hyperlipidemia. Additional features include short stature, thin arms and legs and xanthomas. Affected females have polycystic ovaries. Adenomas may form in the liver of adult patients. Diagnosis is made by measuring the levels of glucose, lactate, triglycerides and uric acids. Moreover, glucose challenge and liver function tests are used. Management includes avoiding hypoglycemia by continuous carbohydrate intake.
Mutations in the SLC37A4 gene cause GSD1B. These mutations prevent the proper breakdown of glucose 6-phosphate, which then gets converted into glycogen and fats. The accumulations of these molecules within the cells damage the liver and kidneys of affected individuals.