Lesch-Nyhan Syndrome

Definition: Lesch-Nyhan syndrome is an inheritable disorder that affects how the body builds and breaks down purines.

Etiology: 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.

Frequency: about 1 in 380,000 people.

Clinical Features: 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 that begins in the second year of life. It is unknown how the enzyme deficiency causes these problems.

Oral Manifestations: The most typical feature results in partial or total destruction of perioral tissues.

Treatment: Treatment for LNS is symptomatic. Gout can be treated with allopurinol to control excessive amounts of uric acid. Kidney stones may be treated with lithotripsy, a technique for breaking up kidney stones using shock waves or laser beams. There is no standard treatment for the neurological symptoms of LNS. Some may be relieved with the drugs carbidopa/levodopa (used to treat Parkinson's disease), diazepam, phenobarbital, or haloperidol (antipsychotic).

Dental Considerations: A soft mouthguard fabricated to prevent the destruction of perioral soft tissues and combined psychiatric pharmacologic therapy proved to have satisfactory results. In extremem cases, teeth may need to be extracted.

Prognosis: 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. Death is usually due to renal failure in the first or second decade of life.