
			Screening & Prevention

Screening and Prevention Intro
Developmental Screening
Infant Social-Emotional Screening
Maternal Depression Screening
Newborn Screening
- Amino Acid Disorders
- Endocrine Disorders
  - Congenital adrenal hyperplasia
  - Congenital hypothyroidism
- Fatty Acid Oxidation Disorders
- Galactosemias
  - Galactosemia
- Hemoglobinopathies
  - Sickle cell disease
- Organic Acidemias

Argininemia

Screening

Tested By

tandem mass spectrometry (MS/MS); sensitivity=NA; specificity=NA

Names

Argininemia

Arginase deficiency (ARG 1)

Hyperargininemia

ICD-9

270.6, Disorder of urea cycle metabolism

One of 5 known urea cycle disorders, all characterized by hyperammonemia, encephalopathy, and respiratory alkalosis. A deficiency, usually near complete absence, of activity of arginase, blocks the final step of the cycle.

Prevalence

about 1/300,000 live births [Argininemia info for professionals, STAR-G]; possibly more frequent among French Canadians and in parts of Japan [Argininemia review, GeneTests.org]

Inheritance

autosomal recessive

Prenatal Testing

DNA testing by amniocentesis or CVS. Enzyme testing by fetal blood sampling.

Other Testing

Genetic testing is possible if the mutations in both parental carriers are known.

Clinical Characteristics

With treatment before a serious hyperammonemic episode, normal clinical and developmental outcome may be possible. Without treatment, symptoms may begin within the first couple months of life or as late as 4 years of age, but most affected children will show slowed growth by 1-3 years of age and subsequent plateauing of cognitive development, followed by progressive loss of milestones and development of severe spasticity. Acute symptoms may occur during prolonged fasting, periods of increased energy demands (fever, stress, lack of sleep), and after meals high in protein.

Initial signs and symptoms may include:

poor appetite,
illness or fussiness following high-protein feedings,
vomiting,
irritability,
lethargy, and
lab findings:
- elevated arginine
- elevated urine orotic acid
- hyperammonemia (though infrequent in the newborn period).

Subsequent signs and symptoms may include:

poor growth,
muscle weakness,
spasticity,
seizures,
mental retardation, and
death (up to 75% live long, though handicapped, lives).

Follow-up on positive screening test

Plasma amino acid analysis and urine orotic acid. Enzyme assay on red blood cells can be used to confirm the diagnosis.

Primary care management

Upon notification of the + screen

Contact the family and evaluate the infant for poor feeding, vomiting, lethargy, tachypnea;
Provide emergency treatment/referral for lethargy, hypotonia, seizures, signs of liver disease (see the ACT Sheet for Argininemia from ACMG (pdf 118kb) for additional information);
To confirm the diagnosis, work with the following service(s): Utah Newborn Screening Program, (801-584-8256); See also Services below;
For evaluation and ongoing collaborative management, consult the following service(s): Metabolic Clinic, (801-585-2457); See also Services below;

If the diagnosis is confirmed

Educate the family regarding signs, symptoms, and the need for urgent care when the infant becomes ill (see Argininemia info for parents, STAR-G);
Assist in implementation and support of a low protein diet and restriction of arginine, supplementation with other amino acids;
Sodium benzoate or phenylbutyrate therapy may help reduce arginine and ammonia levels;
Periodic monitoring of amino acid and ammonia levels may be indicated;
For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions.

Specialty Care Management

Initial consultation and ongoing collaboration with the following service(s): Metabolic Clinic, (801-585-2457); See also Services below. A dietician may work with the family to devise an optimal approach to dietary management.

Resources

Links

For Professionals

Argininemia info for professionals, STAR-G
On the Screening, Technology and Research in Genetics (STAR-G) site, one of a series of Disorder Fact Sheets for Professionals; structured list of information about the condition, with links to more information.

ACT Sheet for Argininemia from ACMG (pdf 118kb)
Developed by the American College of Medical Genetics (ACMG), includes recommended responses to positive newborn screening test results, diagnostic evaluation, clinical expectations, and sources of additional information. See the ACMG ACT Sheets and Confirmatory Algorithms (link elsewhere on this page) for more info and sheets on other conditions.

ACMG ACT Sheets and Confirmatory Algorithms
The American College of Medical Genetics (ACMG) has developed ACTion (ACT) Sheets and algorithms for responding to positive newborn screening test results. This page contains a table with links to all of the ACT Sheets and related algorithms.

Argininemia Emergency Protocol
A protocol for management of the patient with a positive screen for argininemia, from the New England Consortium of Metabolic Programs.

Argininemia review, GeneTests.org
Excellent review by Stephen Cederbaum, MD including clinical description, differential, management, genetic counseling, molecular genetics, and a bibliography.

Utah Newborn Screening Program
The site provides information and statistics about the program and related legislation, training for practices, and the conditions screened for.

For Parents

Argininemia info for parents, STAR-G
From the Screening, Technology and Research in Genetics (STAR-G) site, providing information for parents about argininemia and links to other sites including parent support groups.

Argininemia, Genetics Home Reference
Excellent, detailed review aimed at patients and families from the National Library of Medicine's Genetics Home Reference site.

National Urea Cycle Disorders Foundation
The National Urea Cycle Disorders Foundation, a non-profit organization, provides support services and information for families; medical lectures on urea cycle disorders; nutrition and medication resources; and information about events and conferences.

For other services related to this condition, browse our Services categories or search our database.

Helpful Articles

PubMed search for articles on argininemia in the last 5 years.

Authors

Reviewing Author:

Nicola Longo MD, PhD, 3/2007

Compiled and edited by:

Alfred Romeo RN, PhD, 3/2007

Content Last Updated:

3/2008

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Argininemia

Disorder Category

Screening

Finding

Tested By

Names

ICD-9

Overview

Prevalence

Inheritance

Prenatal Testing

Other Testing

Clinical Characteristics

Follow-up on positive screening test

Primary care management

Upon notification of the + screen

If the diagnosis is confirmed

Specialty Care Management

Resources

Links

For Professionals

For Parents

Services

Newborn Screening Programs

Pediatric Genetics

Helpful Articles

Authors