Hereditary fructose intolerance
Fructosemia; Fructose intolerance; Fructose aldolase B-deficiency; Fructose-1, 6-bisphosphate aldolase deficiencyHereditary fructose intolerance is a disorder in which a person lacks the protein needed to break down fructose. Fructose is a fruit sugar that naturally occurs in the body. Man-made fructose is used as a sweetener in many foods, including baby food and drinks.
Causes
This condition occurs when the body is missing an enzyme called aldolase B. This substance is needed to break down fructose.
If a person without this substance eats fructose or sucrose (cane or beet sugar, table sugar), complicated chemical changes occur in the body. The body cannot change its stored form of sugar (glycogen) into glucose. As a result, blood sugar falls and dangerous substances build up in the liver.
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.
Symptoms
Symptoms can be seen after a baby starts eating food or formula.
The early symptoms of fructose intolerance are similar to those of galactosemia (inability to use the sugar galactose). Later symptoms relate more to liver disease.
Galactosemia
Galactosemia is a condition in which the body is unable to use (metabolize) the simple sugar galactose.
Read Article Now Book Mark ArticleSymptoms may include:
- Convulsions
Convulsions
A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...
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- Irritability
Irritability
Young children who cannot talk yet will let you know when something is wrong by acting fussy or irritable. If your child is fussier than usual, it c...
Read Article Now Book Mark Article - Yellow skin or whites of the eyes (jaundice)
- Poor feeding and growth as a baby, failure to thrive
Failure to thrive
Failure to thrive refers to children whose current weight or rate of weight gain is much lower than that of other children of similar age and sex....
Read Article Now Book Mark Article - Problems after eating fruits and other foods that contain fructose or sucrose
- Vomiting
Vomiting
Nausea is feeling an urge to vomit. It is often called "being sick to your stomach. "Vomiting or throwing-up forces the contents of the stomach up t...
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Exams and Tests
Physical examination may show:
- Enlarged liver and spleen
- Jaundice
Tests that confirm the diagnosis include:
- Blood clotting tests
- Blood sugar test
Blood sugar test
A blood sugar test measures the amount of a sugar called glucose in a sample of your blood. Glucose is a major source of energy for most cells of the...
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- Genetic testing
- Kidney function tests
Kidney function tests
Kidney function tests are common lab tests used to evaluate how well the kidneys are working. Such tests include:BUN (Blood urea nitrogen) Creatinin...
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Liver function tests
Liver function tests are common tests that are used to see how well the liver is working. Tests include:AlbuminAlpha-1 antitrypsinAlkaline phosphata...
Read Article Now Book Mark Article - Liver biopsy
Liver biopsy
A liver biopsy is a test that takes a sample of tissue from the liver for examination.
Read Article Now Book Mark Article - Uric acid blood test
Uric acid blood test
Uric acid is a chemical created when the body breaks down substances called purines. Purines are normally produced in the body and are also found in...
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Urinalysis
Urinalysis is the physical, chemical, and microscopic examination of urine. It involves a number of tests to detect and measure various compounds th...
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Blood sugar will be low, especially after receiving fructose or sucrose. Uric acid levels will be high.
Treatment
Removing fructose and sucrose from the diet is an effective treatment for most people. Complications may be treated. For example, some people can take a medicine to lower the level of uric acid in their blood and decrease their risk for gout.
Outlook (Prognosis)
Hereditary fructose intolerance may be mild or severe.
Avoiding fructose and sucrose helps most children with this condition. The prognosis is good in most cases.
A few children with a severe form of the disease will develop severe liver disease. Even removing fructose and sucrose from the diet may not prevent severe liver disease in these children.
How well a person does depends on:
- How soon the diagnosis is made
- How soon fructose and sucrose can be removed from the diet
- How well the enzyme works in the body
Possible Complications
These complications may occur:
- Avoidance of fructose-containing foods due to their effects
- Bleeding
- Gout
- Illness from eating foods containing fructose or sucrose
- Liver failure
- Low blood sugar (hypoglycemia)
Hypoglycemia
Low blood sugar is a condition that occurs when the body's blood sugar (glucose) decreases and is too low. Blood sugar below 70 mg/dL (3. 9 mmol/L) i...
Read Article Now Book Mark Article - Seizures
Seizures
A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...
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When to Contact a Medical Professional
Contact your health care provider if your child develops symptoms of this condition after feeding starts. If your child has this condition, experts recommend seeing a doctor who specializes in biochemical genetics or metabolism.
Prevention
Couples with a family history of fructose intolerance who wish to have a baby may consider genetic counseling.
Most of the damaging effects of the disease can be prevented by decreasing fructose and sucrose intake.
References
Bonnardeaux A, Bichet DG. Inherited disorders of the renal tubule. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 44.
Kishnani PS, Chen Y-T. Defects in metabolism of carbohydrates. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 105.
Mojica A, Weinstock RS. Carbohydrates. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2022:chap 17.
Scheinman SJ. Genetically based kidney transport disorders. In: Gilbert SJ, ed. National Kidney Foundation's Primer on Kidney Disease. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 37.
Review Date: 4/24/2023
Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.