Which enzyme is deficient in hereditary fructose intolerance?
Which enzyme is deficient in hereditary fructose intolerance?
Hereditary fructose intolerance (HFI) is a metabolic disease caused by the absence of an enzyme called aldolase B. In people with HFI, ingestion of fructose (fruit sugar) and sucrose (cane or beet sugar, table sugar) causes severe hypoglycemia (low blood sugar) and the build up of dangerous substances in the liver.
Why aldolase deficiency is more severe in fructose metabolism and causes hypoglycemia?
In individuals deficient in aldolase B activity, this causes an accumulation of fructose-1-phosphate, leading to subsequent inhibition of both glycolytic and gluconeogenesis pathways, thus causing hypoglycemia in individuals.
What causes aldolase B deficiency?
Fructose intolerance is an autosomal recessive disease, caused by a genetic defect in fructose 1-phosphate aldolase (aldolase B) in the liver. The symptoms of aldolase B deficiency start when the infant is exposed to fructose.
What does aldolase B do?
Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into glyceraldehyde and dihydroxyacetone phosphate. To a lesser degree, aldolase B is also involved in the breakdown of the simple sugar glucose.
How do you know if you have hereditary fructose intolerance?
After ingesting fructose, individuals with hereditary fructose intolerance may experience nausea, bloating, abdominal pain, diarrhea, vomiting, and low blood sugar (hypoglycemia). Affected infants may fail to grow and gain weight at the expected rate (failure to thrive).
Does hereditary fructose intolerance run in families?
Hereditary fructose intolerance is inherited, which means it can be passed down through families. If both parents carry a nonworking copy of the aldolase B gene, each of their children has a 25% (1 in 4) chance of being affected.
What causes hereditary fructose intolerance?
Mutations in the ALDOB gene cause hereditary fructose intolerance. The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is found primarily in the liver and is involved in the breakdown (metabolism) of fructose so this sugar can be used as energy.
When does hereditary fructose intolerance occur?
Hereditary Fructose Intolerance may be diagnosed at birth or shortly thereafter when the infant is weaned. Like other autosomal disorders it is equally distributed among males and females. Estimates of the incidence of the disorder range widely from 1:10,000 to 1:100,000 births.
Why is hereditary fructose intolerance symptomatic?
Individuals affected with HFI are asymptomatic until they ingest fructose, sucrose, or sorbitol. If fructose is ingested, the enzymatic block at aldolase B causes an accumulation of fructose-1-phosphate which, over time, results in the death of liver cells.
Can you suddenly become fructose intolerance?
Hereditary fructose intolerance is a rare autosomal recessive disorder and, while most people are not born with it, its occurrence later in life is very common.
Do avocados have fructose?
Half an avocado, or 100 g, contains just 0.66 g of sugar, which includes glucose, fructose, sucrose, and galactose. The net digestible carbs are only 1.8 g for each 100 g of avocado.
How do I know if I have hereditary fructose intolerance?
Symptoms
- Convulsions.
- Excessive sleepiness.
- Irritability.
- Yellow skin or whites of the eyes (jaundice)
- Poor feeding and growth as a baby, failure to thrive.
- Problems after eating fruits and other foods that contain fructose or sucrose.
- Vomiting.
What gene is involved in fructose intolerance?
Mutations in the ALDOB gene cause hereditary fructose intolerance. The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is found primarily in the liver and is involved in the breakdown (metabolism) of fructose so this sugar can be used as energy.
What is the function of aldolase B?
Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into other molecules called glyceraldehyde and dihydroxyacetone phosphate. ALDOB gene mutations reduce the function of the enzyme, impairing its ability to metabolize fructose.
The HFI Laboratory at Boston University provides information on the diagnosis of hereditary fructose intolerance. Orphanet lists international laboratories offering diagnostic testing for this condition. Complete elimination of fructose and sucrose from the diet is an effective treatment for most people, [1] although this can be challenging.
What is the function of the ALDOB gene?
The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is found primarily in the liver and is involved in the breakdown (metabolism) of fructose so this sugar can be used as energy.