• Turnaround time:
    10–21 calendar days (14 days on average)
  • Preferred specimen:
    3mL whole blood in a purple-top tube
  • Alternate specimens:
    DNA or saliva/assisted saliva
  • Sample requirements
  • Request a sample kit



Associated disorders

The OTC gene is associated with X-linked ornithine transcarbamylase (OTC) deficiency (MedGen UID: 75692).

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Order this gene as a single gene test.

OTC: Analysis includes the intronic variant NM_000531.5:c.540+265G>A.

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Invitae tests that include this gene:

Pathogenic variants in the OTC gene are the only known cause of ornithine transcarbamylase (OTC) deficiency, which accounts for an estimated 59% of all urea cycle disorder diagnoses.

The OTC gene encodes the ornithine transcarbamylase enzyme which catalyzes the third step of the urea cycle. More specifically this mitochondrial enzyme converts carbamoyl phsophate and ornithine to citrulline and phosphate. The urea cycle is an important mechanism for the conversion of neurotoxic ammonia, a byproduct of protein degradation, to non-toxic urea, which can be safely removed from the body.

Assay and technical information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons, +/- 10 base pairs of adjacent intronic sequence, and select noncoding variants. Our assay provides a Q30 quality-adjusted mean coverage depth of 350x (50x minimum, or supplemented with additional analysis). Variants classified as pathogenic or likely pathogenic are confirmed with orthogonal methods, except individual variants that have high quality scores and previously validated in at least ten unrelated samples.

Our analysis detects most intragenic deletions and duplications at single exon resolution. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. If you are requesting the detection of a specific single-exon copy number variation, please contact Client Services before placing your order.

Gene Transcript reference Sequencing analysis Deletion/Duplication analysis
OTC* NM_000531.5

*OTC: Analysis includes the intronic variant NM_000531.5:c.540+265G>A.