Any of a group of relatively rare hereditary disorders of fat metabolism in which enzyme defects cause distinctive types of lipids to accumulate. They include Tay-Sachs disease, Gaucher disease, Niemann-Pick disease, and Fabry disease. Several are untreatable and cause death before age five; others occur in adulthood.
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Any of numerous types of hereditary enzyme deficiency resulting in altered metabolism of glycogen. The problems are classified in two groups, those affecting the liver and those involving striated muscle, both primary glycogen storage sites. Symptoms in the liver group range from symptomatic hypoglycemia with ketosis to asymptomatic liver enlargement (hepatomegaly). In the muscle group, they range from weakness and cramps to fatal heart enlargement.
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