Test Overview
Test Methodology

The entire targeted gene(s) are sequenced with Illumina sequencing by synthesis (SBS) chemistry, using the Illumina DNA PCR-Free Tagmentation based whole genome sequencing (WGS) library preparation. Sequences are mapped and aligned to genome reference consortium human build 38 (GRCh38, hg38); variants are called by Illumina DRAGEN germline pipeline and analyzed with the assistance of Illumina Emedgene tertiary analysis pipeline. Average depth of coverage is ≥30x. A minimum sequencing depth of 10x is achieved for all coding regions (+/-15 bp). Regions not meeting these depth metrics are further assessed by either Sanger sequencing or manual review. Sequence variants of potential clinical significance, based on the ACMG/AMP guidelines (PMID: 25741868) and ClinGen specifications (clinicalgenome.org/working-groups/sequence-variant-interpretation), are reported. Copy number variation (CNV) of potential clinical significance, based on the ACMG/ClinGen standards (PMID: 31690835), are reported. All reported variants not meeting the quality criteria are confirmed by a different technology.

Test Usage

Follow up gene sequencing for positive Newborn Screening (NBS) results suggestive of Citrullinemia Type 1 (aka argininosuccinate synthetase (ASS) deficiency) due to citrulline elevation.

Establishing a molecular diagnosis for an individual with, or a known family history of, Citrullinemia Type 1 (aka argininosuccinate synthetase (ASS) deficiency).

Gene List: ASS1

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Minimum depth coverage metrics do not apply to regulatory elements or deep intronic regions of the targeted gene(s); thus, variants in those regions may not be detected. Balanced structural variants are generally not analyzed. Furthermore, variants outside of the targeted gene(s) are not analyzed. This analysis may not reliably detect mosaicism or CNV in regions with pseudogene interference. Variant classification reflects the current state of scientific understanding at the time of test completion; when new scientific data are available, the interpretation and classification of variants may change. Test interpretation may be impacted by the presence of a hematologic malignancy or an allogenic bone marrow transplant.

Test Details
Days Set Up
Various days Monday – Friday
Analytic Time

10 days

Soft Order Code
ASS1
MiChart Code
ASS1 Gene sequencing
Synonyms
    Laboratory
    MMGL
    Section
    MMGL Molecular Genetics
    Specimen Requirements
    Collection Instructions

    Collect blood specimen in a EDTA lavender top tube. Send it within 24 hours if stored at room temperature or within 5 days if stored refrigerated.

    Fill out a MLabs Molecular test requisition (or place an e-order if applicable):
    https://mlabs.umich.edu/media/166
    Fill out a Clinical History Form for Insurance Prior Authorization (include all required documentation indicated at the bottom of this form):
    https://mlabs.umich.edu/sites/default/files/2020-08/file/mlab11618clini…
    Fill out a UMHS Request and Consent for Genetic Testing form:
    https://mlabs.umich.edu/sites/default/files/2023-04/file/germline-conse…
    Michigan State law requires the ordering provider to obtaining informed consent from the patient prior to prognostic or predictive genetic testing. Contact a MLabs Client Services Center at 800-862-7284 to request paper copies or to setup a client account.

    Alternate Specimen

    Cheek swab kit (Oragene OCD-100), follow collection instructions.
    Saliva kit (Oragene OGD-510), follow collection instructions.

    Contraindications
    This test should not be ordered for phenotypically normal individuals or individuals with a normal newborn screening result.
    Normal Volume

    5 mL whole blood

    Minimum Volume

    1 mL whole blood (0.5 mL infants)

    Storage Temperature
    Room temperature up to 24 hours or 2-8°C up to 5 days for blood
    2-36°C for saliva
    Rejection Criteria
    Hemolyzed blood sample. Fresh tissue (POC) or paraffin embedded specimens are not acceptable.
    Additional Information

    Most insurance carriers require prior authorization for genetic testing. Testing will not begin until insurance prior authorization is received by the laboratory or it is confirmed that prior authorization is not required. The ordering health care provider can obtain the prior authorization or request the laboratory to submit it. To obtain BCN prior authorization call Joint Venture Hospital Laboratories (JVHL) at 800-445-4979; for all other insurances, contact the plan directly. By ordering this test the clinician acknowledges that informed consent, https://mlabs.umich.edu/sites/default/files/2023-04/file/germline-conse…, has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes medical geneticist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

    Billing
    CPT Code
    81406
    Fee Code
    DA216
    Pro Fee CPT
    G0452-26
    NY State Approved
    No