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Urea Cycle Disorders At a Glance

Ashley

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The GEMSS website is intended primarily for educators and families of preschool through elementary 
school age children. While much of the information may also apply to older children, the authors are 
aware that there is a lack of information about transition issues that would be helpful for older 
children and young adults. It is our hope that this information can be added in the futur
 
The GEMSS website is intended primarily for educators and families of preschool through elementary 
school age children. While much of the information may also apply to older children, the authors are 
aware that there is a lack of information about transition issues that would be helpful for older 
children and young adults. It is our hope that this information can be added in the futur

Urea cycle disorders are a group of genetic conditions that fall under the broad category of metabolic disorders. The urea cycle is a biochemical process that occurs in the liver. Through this process, body waste from the metabolism of protein (in the form of nitrogen) is removed from the blood and converted to a compound called urea. There are eight enzymes that complete this process, and normally the urea is transferred into the urine and removed from the body. 

However, in urea cycle disorders, one of the enzymes in the cycle is deficient. Without the proper enzymes, the process can't be completed, and nitrogen accumulates in the blood in the form of ammonia, a highly toxic substance. The accumulation of ammonia in the blood is called hyperammonemia. Hyperammonemia is especially toxic to the brain and can cause brain damage, coma or death. 

UCDs are caused by a genetic mutation. Some children are diagnosed as children because they show symptoms. Other children are diagnosed as infants through new-born screening (NBS). Children diagnosed by NBS may receive treatment before they first experience symptoms. 

Learn More about Types of UCDs