About UCD

Prescribing Information

Patient Information

Types of UCDs

Treatment Guidelines

TYPES of UCDS

Many of the urea cycle disorders have similar symptoms because they affect the body in the same way.¹ In diagnosing and managing UCDs, physicians typically identify the specific enzyme that is deficient or absent. A description of those enzymes and associated symptom onset are provided below.

Symbol	Name	Prevalence/ Inheritance^2-4	Symptom Onset^1,4
CPS	Carbamyl Phosphate Synthetase Deficiency	1:62,000/ Autosomal recessive	Complete Deficiency: 24-72 hrs. after birth Partial Deficiency: Infancy to Adulthood
OTC	Ornithine Transcarbamylase Deficiency⁶	1:14,000/ X-linked	Hemizygote males: onset in 24-72 hrs. after birth Heterozygote females: 25% are symptomatic. Milder forms usually occur after infancy.
ASS	Argininosuccinate Synthetase Deficiency⁷ (Citrullinemia)	1:57,000/ Autosomal Recessive	Complete Deficiency: 24-72 hrs. after birth Partial Deficiency: Infancy to Adulthood
ASL	Argininosuccinate Lyase Deficiency (Argininosuccinc Acidura)	1:70,000/ Autosomal Recessive	Complete Deficiency: 24-72 hrs. after birth Partial Deficiency: Infancy to Adulthood
ARG	Arginase Deficiency	1:363,000/ Autosomal Recessive	Infants usually remain asymptomatic in the first few months or, sometimes, years of life. Often present with symptoms of loss of muscle control. Mental retardation is progressive and seizures are common. Episodes of severe hyperammonemia not usually seen.³
NAGS	N-Acetylglutamate Synthase Deficiency⁸	Few Cases Worldwide/ Autosomal recessive	Complete Deficiency: 24-72 hrs. after birth Partial Deficiency: Infancy to Adulthood, with a stressful triggering event such as an infection or a viral illness.

*Hemizygote: nucleus, cell, or organism that has only one of a normally diploid set of genes.
†Heterozygote: an individual with two different alleles at a given locus on a pair of homologous genes. Seen in X-linked diseases.

Click here for important safety information

Click here for Full Prescribing Information

References

1. UCDC for Patients page. Urea Cycle Disorders Consortium Web page. Available at: http://rarediseasesnetwork.epi.usf.edu/ucdc/learnmore/definitions.htm. Accessed September 26, 2007.

2. Brusilow SW, Horwich AL. Urea Cycle Enzymes. In: Scriver C, Beaudet, Sly, et al. eds. The Metabolic and Molecular Bases of Inherited Disease. 8th ed. New York, NY: McGraw-Hill; 2001:1909-1963.

3. Rezvani I. Urea cycle and hyperammonemia (arginine, citrulline, ornithine). In: Berhman RE, Kliegman RM, Jensen HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: Saunders Elsevier; 2004:Chapter 74.

4. Cederbaum SD. Diseases of the urea cycle. In: Cecil Textbook of Medicine. 22nd ed. Philadelphia, Pa: Saunders Elsevier; 2004:Chapter 220.

5. Roth K S Carbamyl phosphate deficiency. eMedicine Web site. March 4, 2004. Available at: http://www.emedicine.com/ped/topic314.htm. Accessed September 26, 2007

6. Roth K S Ornithine transcarbamylase deficiency. eMedicine Web site. May 20, 2003. Available at: http://www.emedicine.com/ped/topic2744.htm. Accessed September 26, 2007.

7. Roth, K S Citrullinemia (argininosuccinate synthetase deficiency). eMedicine Web site. July 10, 2003. Available at: http://www.emedicine.com/ped/topic406.htm. Accessed September 26, 2007.

8. Roth, K S Argininosuccinate lyase deficiency. eMedicine Web site. July 10, 2003. Available at: http://www.emedicine.com/ped/topic2745.htm. Accessed September 26, 2007.

9. Roth, K S N-acetylglutamate synthetase deficiency. eMedicine Web site. May 20, 2003. Available at: http://www.emedicine.com/ped/topic10.htm. Accessed September 26, 2007.