Argininemia

Argininemia

Argininemia is a rare autosomal recessive metabolic disorder that is characterized by a deficiency in the enzyme arginase, which is part of the urea cycle. This condition leads to an accumulation of arginine and ammonia in the blood, resulting in a variety of symptoms and complications.

Pathophysiology

Argininemia is caused by mutations in the ARG1 gene, which provides instructions for making the enzyme arginase. Arginase is responsible for breaking down arginine into ornithine and urea, a process that is crucial for the removal of excess nitrogen from the body. In individuals with argininemia, the lack of functional arginase leads to elevated levels of arginine and ammonia, which can be toxic to the body, particularly the nervous system.

Symptoms

The symptoms of argininemia can vary but often include:

• Developmental delay
• Intellectual disability
• Spasticity
• Seizures
• Growth retardation
• Microcephaly

These symptoms typically appear in early childhood, although the severity and onset can vary among individuals.

Diagnosis

Argininemia is diagnosed through a combination of clinical evaluation, biochemical tests, and genetic testing. Elevated levels of arginine in the blood and urine are indicative of the disorder. Genetic testing can confirm mutations in the ARG1 gene.

Treatment

Management of argininemia involves dietary restrictions to limit arginine intake and the use of medications to reduce ammonia levels. A low-protein diet supplemented with essential amino acids, excluding arginine, is often recommended. Medications such as sodium benzoate or sodium phenylbutyrate may be used to help remove excess ammonia from the body.

Prognosis

The prognosis for individuals with argininemia varies depending on the severity of the condition and the effectiveness of treatment. Early diagnosis and management can improve outcomes and reduce the risk of severe complications.

Related pages

• Urea cycle disorder
• Metabolic disorder
• Autosomal recessive disorder

Gallery

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  Diagram illustrating the urea cycle, highlighting the role of arginase.

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  Structure of Arginine

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  Autosomal Recessive Inheritance Pattern

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  Structure of Glycerol Phenylbutyrate