Lesch-Nyhan syndrome Health Article

Definition

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.

Symptoms

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:

• Overexaggerated reflexes
• Spasticity

Blood and urine tests may reveal high uric acid levels. A skin biopsy may show decreased levels of the HGP enzyme.

Treatment

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.