Ornithine transcarbamylase deficiency
|Disorder||Orthnithine transcarbamylase deficiency|
Biochemical abnormalities associated with OTC deficiency include hyperammonemia, low citrulline and arginine, and elevated urinary orotic acid. Since OTC is an X-linked disorder, male infants are primarily affected usually presenting in the first few days of life with lethargy, anorexia, seizures, neurologic posturing, abnormal breathing, and coma related to cerebral edema. Long-term prognosis depends on the initial duration of the hyperammonemia. About 15% of carrier females will develop hyperammonemia, which may or may not require chronic medical management.
|Indications||Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation within a family to allow for carrier testing and prenatal diagnosis.|
|Associated Tests||Plasma amino acids and urine orotic acid are available through the Biochemical Lab.
The OTC gene is also plart of the XLID 92-gene panel.
|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|
|Transport||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 collected on Friday can be safely designated for Monday delivery|
|Turnaround time||Sequencing: 6 weeks|
|Prenatal testing||Prenatal diagnosis is available if the familial mutation is known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.|
|CPT Codes||Unknown mutation
|Cost||$1100 for sequencing
$350 for known mutation
Prenatal diagnosis for a known mutation is $1000. Please contact the lab for more information.
Molecular Diagnostic Lab
The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.