Diagnosis and Testing
How do I get my child tests for argininemia?
Argininemia can be diagnosed after a positive result from newborn screening. During routine newborn screening, a tiny sample of blood is taken from the heel of a newborn. This test called a heel prick or Guthrie test involves getting a few drops of blood from a pinprick in the newborn's heel. The blood is run through a machine that can detect high levels of arginine, an amino acid that abnormally builds up in people with argininemia. Sometimes, newborn screening may miss an infant with argininemia, and sometimes there may be a false positive.
Additional tests will be performed to confirm the diagnosis. These tests involve looking at the blood and urine for substances that are abnormally elevated in argininemia including arginine and orotic acid. The blood may be tested to see if the activity of the arginase enzyme is reduced. This is called an enzyme assay.
Doctors may also conduct molecular genetic testing on infants with argininemia. These tests involve studying the ARG1 gene for changes (mutations) that cause the disorder. This can include sequence analysis, where a part or sequence of DNA within a gene is examined, or deletion/duplication analysis, where missing or extra regions of DNA are looked for within a specific gene. Molecular genetic testing must be done at specialized laboratories.
If you believe your child may have argininemia, talk to your pediatrician or a genetic counselor about your concerns. They can help decide if testing is right for you, and can order this testing if necessary.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/argininemia/diagnosis-testing/36491 • DATE UPDATED: 2019-06-17
Arginase Deficiency. The National Organization for Rare Disorders website. https://rarediseases.org/rare-diseases/arginase-deficiency
Wong D, Cederbaum S, Crombez EA. Arginase Deficiency. GeneReviews website. https://www.ncbi.nlm.nih.gov/books/NBK1159
The National Urea Cycle Disorders Foundation website
The Genetics and Rare Diseases Information Center website