Pentosuria

A rare metabolic condition involving the excretion of xylulose in urine

Pentosuria

Pentosuria is a rare metabolic disorder characterized by the excessive excretion of the pentose sugar xylulose in the urine. This condition is often benign and does not typically result in any significant health problems. Pentosuria is most commonly found in individuals of Ashkenazi Jewish descent.

Chemical structure of xylulose

Pathophysiology

Pentosuria is caused by a deficiency in the enzyme xylitol dehydrogenase, which is responsible for the metabolism of xylulose. In individuals with pentosuria, xylulose is not properly metabolized and is instead excreted in the urine. This can lead to a false positive result for glucose in urine tests, as the presence of xylulose can be mistaken for glucose.

Genetics

Pentosuria is inherited in an autosomal recessive pattern. This means that an individual must inherit two copies of the defective gene, one from each parent, to manifest the condition. The gene responsible for pentosuria has been mapped to a specific location on chromosome 2.

Diagnosis

The diagnosis of pentosuria is typically made through a combination of clinical evaluation and laboratory testing. A urinalysis can reveal the presence of pentose sugars, and specific tests can differentiate xylulose from glucose. Genetic testing can confirm the diagnosis by identifying mutations in the gene responsible for the condition.

Management

Since pentosuria is generally a benign condition, no specific treatment is required. Patients are usually advised to inform healthcare providers of their condition to avoid misdiagnosis of diabetes mellitus due to the presence of reducing sugars in the urine.

Related pages

• Metabolic disorder
• Xylulose
• Autosomal recessive disorder
• Urinalysis