Citrullinemia, Type 1 (ASS1) Sequencing
Lab
studies request form |
CPT Codes/Price
List (PDF)
Citrullinemia type I is an inborn error of amino acid metabolism caused by the deficiency of argininiosuccinate synthase (ASS1), which performs the third enzymatic step in the urea cycle, condensing citrulline and aspartic acid to form argininosuccinic acid. Patients are often identified by newborn screening, due to an accumulation of citrulline in the blood.
Citrullinemia type I exhibits a broad clinical spectrum. Most patients present with a severe neonatal form characterized by hyperammonemia, vomiting, lethargy, failure to thrive, seizures, spasticity and increased intracranial pressure. Patients typically progress quickly to a coma and the disorder is fatal unless treated promptly. Other patients may exhibit a milder later-onset form of the disorder, and others appear to be asymptomatic.
ASS1 sequencing will detect mutations in approximately 96% of alleles in patients with citrullinemia type I and is available from the Metabolic Laboratory of the Greenwood Genetic Center. Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.
Specimen requirements: 5 to 10 mL of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 mL. If necessary, ACD solution A Vacutainer tubes (yellow top) may be submitted. Please contact the laboratory for more information.
Transport: Please contact Tim Wood or the molecular diagnostic lab coordinator (1-800-473-9411) for shipping information. The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples on Friday can be safely designated for Monday delivery.
Analysis standards: Analysis will be complete within 4 weeks of sample receipt. The lab director assesses the quality and interpretation of results. Technical staff members independently assess the quality and interpretation of the test. The Greenwood Genetic Center Metabolic Diagnostic Laboratory is CLIA certified and actively participates in CAP proficiency surveys.
Reporting of Test Results: Test results with interpretation will be mailed and/or faxed following completion of the test. Verbal reports will be telephoned to the person(s) requesting the test when an abnormal test result occurs. Consultation with the laboratory director and explanations of testing protocols will be supplied upon request.
CPT Codes: 83890, 83898(x8), 83904(x9), 83909(x9), 83912
|
|
