- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Classic OTC deficiency is a urea cycle disorder characterized by hyperammonemia, cyclical vomiting, seizures, lethargy, coma and neonatal death if not treated. Clinical presentation varies widely in females, and some males can have non-classical forms.
Incidence: Approximately 1 in 20,000.
Penetrance: Variable depending on sex and mutation.
Cause: Pathogenic OTC gene mutations.
Clinical Sensitivity: Approximately 80 percent.
Methodology: Bidirectional sequencing of the entire OTC coding region and intron/exon boundaries.
Analytical Sensitivity and Specificity: 99 percent.
Limitations:Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected in individuals of both sexes; large deletions/duplications will not be detected in females.
|Component Test Code*||Component Chart Name||LOINC|
|2004902||OTC Deficiency (OTC) Seq Specimen|
|2004903||OTC Deficiency (OTC) Seq Interpretation|
- OTC Sequencing
- Urea Cycle Defect