Hereditary Fructose Intolerance
Hereditary Fructose Intolerance
Also known as:HFI, ALDOB-Related Fructose Intolerance, Hereditary Fructose Metabolism Disorder
Hereditary Fructose Intolerance is an ALDOB-related fructose metabolism disorder. Ingestion of fructose, sucrose, or sorbitol may cause vomiting, low blood sugar, liver and kidney damage, among other risks.
Start Here
A quick guide to the next step: which department to start with, what to prepare, and what to ask.
When infants develop repeated vomiting, sweating, drowsiness, hypoglycemia, or abnormal liver function after introduction of fruits, juice, sucrose-containing foods, or certain formulas/medications, they should be evaluated by a metabolic genetics specialist, pediatric gastroenterology/hepatology department, or emergency department.
HFI is related to insufficient aldolase B function. Fructose metabolism intermediates accumulate in the liver, kidneys, and intestines, which can lead to hypoglycemia, vomiting, abnormal liver function, and long-term organ damage.
Yes, there is a clear dietary avoidance and nutritional follow-up management pathway. Fructose loading tests should not be performed when HFI is suspected, and a safe dietary plan should be developed by metabolic specialists and dietitians.
Yes, typically autosomal recessive inheritance, related to biallelic pathogenic ALDOB variants.
Often mistaken for picky eating, gastroenteritis, food allergies, lactose intolerance, or ordinary hypoglycemia; children may naturally dislike sweet foods and fruits, which can mask important clues.
This page helps patients and families organize care leads. It does not replace a clinician’s diagnosis or treatment plan. For testing, medication, referrals, emergency care, and support applications, follow qualified clinicians, medical institutions, support organizations, and official sources.
Diagnosis Path
Organized around the practical patient journey: identify clues, avoid common delays, then prepare for care.
When to Suspect It
- Vomiting, sweating, drowsiness, or hypoglycemia after consuming fruits, juice, sweets, sucrose, or sorbitol-containing ingredients.
- Repeated abdominal pain, bloating, food refusal, poor weight gain, or enlarged liver after infant feeding.
- Unexplained abnormal liver function, jaundice, coagulation abnormalities, hypoglycemia, or kidney problems related to diet.
- A child who clearly dislikes sweet foods, fruits, or sugar-containing foods and has a history of discomfort after eating them.
- Family history of HFI, infant hypoglycemia, liver or kidney damage, or consanguinity.
Common Wrong Turns
- Attributing symptoms to ordinary gastroenteritis or food allergies without asking about specific carbohydrate components.
- Repeatedly attempting to "train" the child to eat fruits and sweets, causing repeated exposure.
- Confusing fructose malabsorption with hereditary fructose intolerance, underestimating the risks of hypoglycemia and liver/kidney damage.
- Using medications, supplements, or oral solutions containing sucrose, fructose, or sorbitol without checking ingredients first.
Departments to Start With
- Metabolic Genetics / Medical Genetics Department
- Pediatric Gastroenterology and Hepatology Department
- Pediatric Emergency Department (when there is risk of hypoglycemia, drowsiness, seizures, or liver failure)
- Nutrition Department (metabolic nutrition specialty)
- Nephrology / Hepatology Department (when organs are affected)
Before the Visit
- Document all foods, formulas, medications, supplements consumed before each episode and the timeline of symptoms.
- Keep records of hypoglycemia, lactate, electrolytes, liver and kidney function, coagulation tests, and urinalysis results.
- Inquire about ALDOB genetic testing; avoid arranging fructose loading tests independently or without specialist guidance.
- Ask a dietitian to help verify ingredients in daily foods, medication excipients, and school/daycare meals.
- When family members have pregnancy plans, prepare genetic reports for genetic counseling.
Tests to Ask About
- ALDOB genetic testing.
- Blood sugar, lactate, electrolytes, uric acid, and acid-base status during hypoglycemic episodes.
- Liver function, bilirubin, coagulation, albumin, and abdominal ultrasound.
- Kidney function, electrolytes, and urinalysis.
- Nutritional status and micronutrient assessment.
Questions for the Doctor
- Do the child's symptoms match HFI? Which ingredients need to be avoided immediately?
- Can genetic testing confirm the diagnosis? Why is a fructose loading test not recommended?
- How should I verify ingredients in daily foods, medications, vaccines, or oral solutions?
- Is there already liver or kidney involvement? How often should follow-up visits be scheduled?
- What genetic counseling is needed for family screening and future pregnancy planning?
Basic Information
Medical Notes
More complete medical explanations are kept here for discussion with clinicians.
Symptoms
HFI often presents with nausea, vomiting, sweating, drowsiness, hypoglycemia, abdominal pain, bloating, food refusal, poor weight gain, and hepatomegaly after exposure to fructose, sucrose, or sorbitol. Repeated exposure may lead to jaundice, abnormal liver function, coagulation problems, and kidney involvement. In severe cases, there may be risk of seizures, coma, or liver/kidney failure.
Diagnosis
Diagnosis relies on symptoms following dietary exposure, metabolic and liver/kidney tests, and ALDOB genetic testing. GeneReviews clearly states that fructose tolerance/loading tests are dangerous and should not be used as routine diagnostic methods. Doctors will also differentiate between fructose malabsorption, food allergies, gastroenteritis, glycogen storage diseases, galactosemia, and other causes of hypoglycemia or liver disease.
Treatment
The core of management is strict avoidance of fructose, sucrose, sorbitol, and related sources, with metabolic dietitians ensuring balanced nutrition and micronutrient supplementation. Acute hypoglycemia or liver/kidney involvement requires hospital-based treatment. All dietary and medication excipient verification should follow specialist protocols.
Long-term Care
Long-term care focuses on food and medication ingredient identification, communication with schools and childcare settings, nutritional status, liver/kidney function, and hypoglycemia prevention. Families may prepare a "list of prohibited ingredients and emergency instructions" to prevent accidental consumption and avoid use of fructose-containing products in medical settings.
Fertility and Family
HFI is autosomal recessive. After identifying ALDOB variants, parents, siblings, and relatives with pregnancy plans can learn about carrier testing, prenatal diagnosis, or preimplantation genetic testing options through genetic counseling.
When to Seek Urgent Care
After accidental ingestion, repeated vomiting, drowsiness, sweating, seizures, hypoglycemia, jaundice, bleeding tendency, reduced urine output, or changes in mental status require immediate emergency care. Clearly communicate suspected or confirmed HFI to avoid continued intake of related carbohydrate sources.
Prognosis
With early identification and avoidance of triggers, most patients can live stable lives; repeated accidental exposure or delayed identification increases the risk of liver/kidney damage.