Disorders of carbohydrate transport and metabolism
Glycogenosis
- any of a group of metabolic disorders characterized by excessive storage of glycogen.
- common hereditary enzyme deficiency causing varying degrees of hemolytic anemia; can cause favism, some drug induced hemolytic anemias, and chronic nonspherocytic hemolytic anemia.
- autosomal recessive disease in which gene expression of glucose-6-phosphatase is absent, resulting in hypoglycemia due to lack of glucose production; accumulation of glycogen in liver and kidney leads to organomegaly, particularly massive hepatomegaly; increased concentrations of lactic acid and hyperlipidemia appear in the plasma; clinical gout often appears in early childhood.
- autosomal recessively inherited glycogen storage disease caused by glucan 1,4-alpha-glucosidase deficiency; large amounts of glycogen accumulate in the lysosomes of skeletal muscle, heart, liver, spinal cord, and brain; three forms have been described: the infantile form is fatal in infancy and presents with hypotonia and a hypertrophic cardiomyopathy; the childhood form usually presents in the second year of life with proximal weakness and respiratory symptoms; the adult form consists of a slowly progressive proximal myopathy.
- autosomal recessive metabolic disorder due to a deficiency in expression of branching enzyme (alpha-1,4-glucan-6-alpha-glucosyltransferase), resulting in an accumulation of abnormal glycogen with long outer branches; clinical features are muscle hypotonia and cirrhosis; death from liver disease usually occurs before age 2.
- glycogenosis due to muscle phosphorylase deficiency; characterized by painful cramps following sustained exercise.
Galactosemia
- group of inherited enzyme deficiencies which feature elevations of galactose in the blood; this condition may be associated with deficiencies of galactokinase, UDP glucose-hexose-1-phosphate uridylyltransferase (classic form), or UDP glucose 4-epimerase; the classic form presents in infancy with failure to thrive, vomiting, and intracranial hypertension; affected individuals also may develop mental retardation, jaundice, hepatosplenomegaly, ovarian failure and cataracts.
Hereditary fructose intolerance
- autosomal recessive fructose metabolism disorder due to deficient fructose-1-phosphate aldolase (EC 2.1.2.13) activity, resulting in accumulation of fructose-1-phosphate; accumulated fructose-1-phosphate inhibits glycogenolysis and gluconeogenesis, causing severe hypoglycemia following ingestion of fructose; prolonged fructose ingestion in infants leads ultimately to hepatic failure and death; patients develop a strong distaste for sweet food, and avoid a chronic course of the disease by remaining on a fructose- and sucrose-free diet.
Intestinal disaccharidase deficiencies and disaccharide malabsorption
- The inability to digest or absorb lactose, a type of sugar found in milk and other dairy products.
Renal glycosuria
Other specified disorders of carbohydrate transport and metabolism
- lysosomal storage disease caused by defective alpha-L-fucosidase and accumulation of fucose containing glycoconjugates; clinical symptoms include psychomotor deterioration, growth retardation, hepatosplenomegaly, cardiomegaly, and seizures.
- Lysosome storage disease due to alpha-L-fucosidase (E.C. 3.2.1.51) deficiency in leukocytes manifested by abnormal accumulation in tissues and urinary excretion of partially catabolized oligosaccharides, glycoasparagines, and glycolipids with alpha-linked fucose at the nonreducing end of the glycogen chain. The phenotype is variable and may include delayed growth and mental development, progressive neurological deterioration, Hurler-like (mucopolysaccharidosis I-H) coarse facies, recurrent infections, visceromegaly, skeletal abnormalities, joint contractures, deafness, and angiokeratoma corporis diffusum. Several types are recognized by different researchers. The form exhibiting a longer survival, mild neurological manifestations, and angiokeratoma is sometimes referred to as fucosidosis type II. In a different scheme, three different types are recognized according to their age of onset. Types I and II are the most severe and have their onsets at 10 and 18 months, respectively with life expectancy of 6 years. Type III represents a juvenile form which is marked by a milder form of psychomotor retardation and a slower deterioration of neurological activities. Hurler-like (gargyloid) facies occur mainly in types I and II and is less commonly in type III.
- either of two genetic disorders characterized by urinary excretion of large amounts of oxalate, with nephrolithiasis, nephrocalcinosis, early onset of renal failure, and often a generalized deposit of calcium oxalate, resulting from a defect in glyoxalate metabolism.
- lysosomal storage disease due to defective alpha-mannosidase with resultant oligosaccharide accumulation.
Unspecified disorder of carbohydrate transport and metabolism
