Essential Fructosuria

What else is it called?

  • Fructokinase deficiency  
  • Ketohexokinase deficiency  
  • Hepatic fructokinase deficiency 
  • Ketohexokinase deficiency  
  • Essential benign Fructosuria  

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Contact our caring team on 08452 412 173 for help and support. Our phone lines open 10am-4pm, Monday to Friday.

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What causes it?

Essential Fructosuria is caused by a deficiency (lack) of the enzyme fructokinase which is responsible for catalysing (cause or accelerating a reaction) fructose to fructose-1-phosphate in the liver. 

 This causes incomplete metabolism (breakdown) of fructose and leads to fructose being excreted (released) in the urine without extra fructose entering the cells. It causes raised levels of fructosemia (presence of fructose in the blood) when fructose or other related sugars (sucrose, sorbitol) are consumed.   

How common is it?

Essential Fructosuria is a rare condition. The prevalence is about 1 in 130,000 births. 

What are the signs and symptoms?

Essential Fructosuria is a condition that shows no symptoms (asymptomatic).   

How is it diagnosed?

Essential Fructosuria is diagnosed accidentally when a non-glucose reducing substance is spotted in the urine by a positive test.  

Can it be treated?

This disorder is clinically benign (nonthreatening) and therefore there is no treatment suggested.

Do my family need to be tested?

Essential Fructosuria is an inherited condition. Humans have chromosomes made up of DNA. Genes are pieces of DNA that carry the genetic information. Each chromosome may have several thousand genes. We inherit chromosomes from the egg of the mother and sperm of the father. The genes on those chromosomes carry the instructions that determine a person’s characteristics, which are a combination of the parents. 

 Carriers of the condition do not have the disorder because the other gene of this pair is working normally. Parents of children with essential fructosuria are carriers.   

The pattern of inheritance in this condition is autosomal recessive. This means:   

When both parents are carriers, the risk to the baby in each pregnancy is  

  • 25% chance (1 in 4) of developing the condition  
  • 50% chance (1 in 2) for the baby to be a carrier of the condition 
  • 25% chance (1 in 4) for the baby to have two working genes and neither have the condition nor be a carrier  

Diagram showing the autosomal recessive inheritance pattern.

Relevant Organisations


References are available on request. Please contact us by phoning 0845 241 2173 or emailing [Resource Library No: ECM006].

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