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Lesch-Nyhan syndrome
Definition
Lesch-Nyhan syndrome is a disorder passed down through families that affects how the body builds and breaks down purines. Purines are a normal part of human tissue and help make up the body's genetic blueprint. They are also found in many different foods.
Causes
Lesch-Nyhan syndrome is passed down through families (inherited) as an X-linked trait. It mostly occurs in boys. Persons with this syndrome are missing or are severely lacking an enzyme called hypoxanthine guanine phosphoribosyltransferase 1 (HGP). The body needs this substance to recycle purines. Without it, abnormally high levels of uric acid build up in the body.
Symptoms
Too much uric acid can cause gout-like swelling in some of the joints. In some cases, kidney and bladder stones develop.
Males with Lesch-Nyhan have delayed motor development followed by abnormal movements and increased reflexes. A striking feature of Lesch-Nyhan syndrome is self-destructive behavior including chewing off fingertips and lips. It is unknown how the disease causes these problems.
Exams and Tests
There may be a family history of this condition.
The doctor or nurse will perform a physical exam. The exam may show:
- Overexaggerated reflexes
- Spasticity
Blood and urine tests may show high uric acid levels. A skin biopsy may show decreased levels of the HGP enzyme.
Treatment
No specific treatment exists for Lesch-Nyhan syndrome. Gout medication (allopurinol) can lower uric acid levels. However, treatment does not improve the neurological outcome.
Some symptoms may be relieved with the following medicines:
- Carbidopa/levodopa
- Diazepam
- Phenobarbital
- Haloperidol
Outlook (Prognosis)
The outcome is likely to be poor. Persons with this syndrome usually need help walking and sitting and generally need a wheelchair.
Possible Complications
Severe, progressive disability is likely.
When to Contact a Medical Professional
Call your health care provider if signs of this illness appear in your child or if there is a history of Lesch-Nyhan syndrome in your family.
Prevention
Genetic counseling for prospective parents with a family history of Lesch-Nyhan syndrome is recommended. Testing can be done to see if a woman is a carrier of this syndrome.
References
Harris JC. Disorders of purine and pyrimidine metabolism. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 83.
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
