Several different problems may lead to the diagnosis, usually by two years of age: * seizures or other manifestations of severe fasting hypoglycemia * hepatomegaly with abdominal protuberance * hyperventilation and apparent respiratory distress due to metabolic acidosis * episodes of vomiting due to metabolic acidosis, often precipitated by minor illness and accompanied by hypoglycemia Once the diagnosis is suspected, the multiplicity of clinical and laboratory features usually makes a strong circumstantial case. If hepatomegaly, fasting hypoglycemia, and poor growth are accompanied by lactic acidosis, hyperuricemia, hypertriglyceridemia, and enlarged kidneys by ultrasound,<unk>  is the most likely diagnosis. The differential diagnosis list includes glycogenoses types III and VI, fructose 1,6-bisphosphatase deficiency, and a few other conditions (page 5), but none are likely to produce all of the features of<unk> . The next step is usually a carefully monitored fast. Hypoglycemia often occurs within six hours. A critical blood specimen obtained at the time of hypoglycemia typically reveals a mild metabolic acidosis, high free fatty acids and beta-hydroxybutyrate, very low insulin levels, and high levels of glucagon, cortisol, and growth hormone. Administration of intramuscular or intravenous glucagon (0.25 to 1 mg, depending on age) or epinephrine produces little rise of blood sugar. The diagnosis is definitively confirmed by liver biopsy with electron microscopy and assay of glucose-6-phosphatase activity in the tissue and/or specific gene testing, available in recent years.
Glycogen storage disease type I
Glycogen storage disease type 0
Glycogen storage disease type V
Glycogen storage disease type VI
Essential fructosuria
Inborn errors of carbohydrate metabolism
Aspartylglucosaminuria
Familial dysbetalipoproteinemia