Essential Pentosuria

What else is it called?

  • Essential benign Pentosuria 
  • L-xylulose reductase deficiencY 
  • L-xylulose 
  • Pentosuria 
  • Xylitol dehydrogenase deficiency 

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What causes it?

The disorder is caused by mutations (changes) in the dicarbonyl and L-xylulose reductase (DCXR) gene. This gene provides instructions for making the DCXR protein which is responsible for converting a sugar called L-xylulose into a molecule called xylitol. This is part of the process in which the body uses sugars for energy.  

 These mutations (changes) in the DCXR gene cause the production of distorted DCXR proteins that are broken down very quickly. Without the DCXR protein, L-xylulose is not transformed into xylitol and the leftover sugar is released in the urine.  

How common is it?

Essential Pentosuriausually occurs only in individuals with Ashkenazi Jewish ancestry. Approximately 1 in 3,300 people in this population are affected. 

What are the signs and symptoms?

Individuals affected by Essential Pentosuria have no related health problems and therefore no symptoms. The only biological sign is the constant release of the enzyme, L-xylulose in the urine, which is often mistaken for a condition called glycosuria, where there is excess sugar in the urine which is typically linked to diabetes or kidney disease  

How is it diagnosed?

The disorder is diagnosed through specialised urine tests by detecting the sugar, L-xylulose in the urine. People with the disorder show an excretion of 1 to 4 grams of L-xylulose in the urine per day.  

Can it be treated?

Essential Pentosuria is benign (unharmful), with no linked health problems and therefore no treatment is needed.  

Do my family need to be tested?

Essential Pentosuria 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 Pentosuria 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: ECM016].

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