Glucose-6-phosphate transport defect

Glycogen storage disease type I (GSDI) is characterized by accumulation of glycogen and fat in the liver and kidneys, resulting in hepatomegaly and renomegaly. The two subtypes (GSDIa and GSDIb) are clinically indistinguishable. Some untreated neonates present with severe hypoglycemia; more commonly, however, untreated infants present at age three to four months with hepatomegaly, lactic acidosis, hyperuricemia, hyperlipidemia, hypertriglyceridemia, and/or hypoglycemic seizures. Affected children typically have doll-like faces with fat cheeks, relatively thin extremities, short stature, and protuberant abdomen. Xanthoma and diarrhea may be present. Impaired platelet function can lead to a bleeding tendency with frequent epistaxis. Untreated GSDIb is associated with impaired neutrophil and monocyte function as well as chronic neutropenia after the first few years of life, all of which result in recurrent bacterial infections and oral and intestinal mucosal ulcers. Long-term complications of untreated GSDI include growth retardation resulting in short stature, osteoporosis, delayed puberty, gout, renal disease, pulmonary hypertension, hepatic adenomas with potential for malignant transformation, polycystic ovaries, pancreatitis, and changes in brain function. Normal growth and puberty is expected in treated children. Most affected individuals live into adulthood.

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