What is the Lyush Nyan Syndrome?

What is Lesch-Nyhan syndrome?

Lesch-Nyhan syndrome is a condition characterized by the overproduction and accumulation of uric acid, a waste product of normal chemical processes that is found in blood and urine. The overproduction of uric acid can cause gouty arthritis (arthritis caused by an accumulation of uric acid in the joints), kidney stones, and bladder stones. Problems with the nervous system and behavioral disturbances are also characteristic of this disorder. Abnormal involuntary muscle movements such as flexing, jerking, and flailing are often displayed by people affected with this disorder. People with Lesch-Nyhan syndrome usually cannot walk, require assistance sitting, and are generally wheelchair-bound. Self-injury, including biting and head banging, is the most common and distinctive behavioral problem in those with Lesch-Nyhan syndrome.

How common is Lesch-Nyhan syndrome?

The prevalence of Lesch-Nyhan syndrome is approximately 1 in 380,000 individuals. This condition occurs with a similar frequency in all populations.

Molecular Genetics

This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

Causes

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.

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.

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.

Reference

http://www.nlm.nih.gov/medlineplus/ency/article/001655.htm
http://www.nationwidechildrens.org/lesch-nyhan-syndrome