Is DNA testing available and/or necessary to diagnose the disorders?
DNA testing is available for all of the disorders, but is not used as a general screening test. DNA testing does not identify responsible genetic changes in all patients. If the plasma amino acids and urine tests do not make the diagnosis, more specialized testing is done. This may include obtaining blood, a skin biopsy or rarely a liver biopsy to measure the suspected missing enzyme or performing a DNA analysis on blood to identify the specific mutation or error causing the enzyme defect. These specialized tests can be obtained at an academic (university based) medical center or Children’s Hospital but will need to be sent out for analysis, usually to one of the sites that are part of the Urea Cycle Disorders Consortium. The enzyme and DNA tests are usually done if a urea cycle disorder is strongly suspected and as yet undiagnosed. The DNA testing may also be done to help in genetic counseling of other family members or in prenatal diagnosis.
DNA testing is available for some of the disorders, but is not used as a general screening test. If the plasma amino acids and urine tests do not make the diagnosis, more specialized testing is done. This may include obtaining blood, a skin biopsy or rarely a liver biopsy to measure the suspected missing enzyme or performing a DNA analysis on blood to identify the specific mutation or error causing the enzyme defect. These specialized tests can be obtained at an academic (university based) medical center or Children’s Hospital but will need to be sent out for analysis, usually to one of the sites that are part of the Urea Cycle Disorders Consortium. The enzyme and DNA tests are usually done if a urea cycle disorder is strongly suspected and as yet undiagnosed. The DNA testing may also be done to help in genetic counseling of other family members or in prenatal diagnosis.
