Lesch-Nyhan syndrome is an inheritable disorder 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, incidence, and risk factors:
Lesch-Nyhan syndrome is 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 enzyme to recycle purines. Without it, abnormally high levels of uric acid build up in the body.
The condition affects about 1 in 380,000 people.
The excess uric acid levels cause children to develop gout-like swelling in some of their joints. In some cases, kidney and bladder stones develop because of the high uric acid levels.
Males with Lesch-Nyhan have delayed motor development followed by bizarre, sinuous movements and increased deep tendon reflexes. A striking feature of Lesch-Nyhan syndrome is self-destructive behavior characterized by chewing off fingertips and lips, if not restrained. It is unknown how the enzyme deficiency causes these problems.
Signs and tests:
There may be a family history of this condition.
The doctor will perform a physical exam. The exam may show:
Blood and urine tests may reveal high uric acid levels. A skin biopsy may show decreased levels of the HGP enzyme.
No specific treatment exists for Lesch-Nyhan syndrome. The gout medication, allopurinol, successfully decreases uric acid levels, but does not improve the neurological outcome.
Some symptoms may be relieved with the drugs carbidopa/levodopa, diazepam, phenobarbital, or haloperidol.
The outcome is likely to be poor. Persons with this syndrome usually require assistance walking and sitting and generally need a wheelchair to get around.
Severe, progressive disability is likely.
Calling your health care provider:
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.
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.
Harris J. Disorders of purine and pyrimidine metabolism. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap. 89.