Assay finds genetic cause of low bile flow


Answers from the Lab

Monogenic cholestasis is characterized by low flow of bile from the liver, which causes liver damage. In this test-specific episode of the "Answers From the Lab" podcast, Devin Oglesbee, Ph.D., explains how Mayo Clinic Laboratories' comprehensive gene panel (Test ID: CHLGP) identifies mutations to guide care for patients with monogenic cholestasis.

"Identifying a genetic cause of cholestasis has been very difficult. This panel aims to simplify the diagnostic path," Dr. Oglesbee says. "Timely diagnosis can help initiate a course of treatment and screening for potential additional health complications."

The panel can detect variants in 112 genes associated with monogenic cholestasis, with high depth coverage. Test components can be customized for the clinical needs of individuals, and each test result includes interpretive comments tailored to the patient.

"There are not many options for genetic testing that are as inclusive or complete as this cholestasis gene panel," Dr. Oglesbee says.


Listen to learn more about Mayo Clinic Laboratories' Cholestasis Gene Panel.

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Testing

Useful information

  • Establishing a molecular diagnosis for patients with monogenic cholestasis.
  • Identifying variants within genes known to be associated with primary, monogenic cholestasis, allowing for predictive testing of at-risk family members.

Specimen requirements

Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

Submit only 1 of the following specimens:

  • Specimen Type: Whole blood
  • Container/Tube:
  • Preferred: Lavender top (EDTA) or yellow top (ACD)
  • Acceptable: Any anticoagulant
  • Specimen Volume: 3 mL
  • Collection Instructions:
  • 1. Invert several times to mix blood.
  • 2. Send whole blood specimen in original tube. Do not aliquot.
  • Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated 14 days
  • Specimen Type: Skin biopsy
  • Supplies: Fibroblast Biopsy Transport Media (T115)
  • Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin (Eagle's minimum essential medium with 1% penicillin and streptomycin).
  • Specimen Volume: 4-mm punch
  • Specimen Stability Information: Refrigerated (preferred)/Ambient
  • Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.
  • Specimen Type: Cultured fibroblast
  • Container/Tube: T-25 flask
  • Specimen Volume: 2 Flasks
  • Collection Instructions: Submit confluent cultured fibroblast cells from a skin biopsy from another laboratory. Cultured cells from a prenatal specimen will not be accepted.
  • Specimen Stability Information: Ambient (preferred)/Refrigerated (<24 hours)
  • Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.
  • Specimen Type: Blood spot
  • Supplies: Card-Blood Spot Collection (Filter Paper) (T493)
  • Container/Tube:
  • Preferred: Collection card (Whatman Protein Saver 903 Paper)
  • Acceptable: PerkinElmer 226 (formerly Ahlstrom 226) filter paper or blood spot collection card
  • Specimen Volume: 5 Blood spots
  • Collection Instructions:
    • An alternative blood collection option for a patient 1 year of age and older is a fingerstick. See How to Collect Dried Blood Spot Samples via fingerstick
    • Let blood dry on the filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.
    • Do not expose specimen to heat or direct sunlight.
    • Do not stack wet specimens.
    • Keep specimen dry.
  • Specimen Stability Information: Ambient (preferred)/Refrigerated
  • Additional Information:
  • Specimen Type: Saliva
  • Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.
  • Supplies: Saliva Swab Collection Kit (T786)
  • Specimen Volume: 1 Swab
  • Collection Instructions: Collect and send specimen per kit instructions.
  • Specimen Stability Information: Ambient 30 days
  • Additional Information: Due to lower concentration of DNA yielded from saliva, it is possible that additional specimen may be required to complete testing.

Performance information

  • Analytic time: 28 to 42 days
  • Day(s) and time(s) performed: Varies

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Barbara J. Toman (@barbaratoman)

Barbara J. Toman

Barbara J. Toman is a Senior Communications Specialist at Mayo Clinic Laboratories. She is also the science writer for Mayo’s Neurosciences Update newsletter, which helps referring physicians to stay informed about Mayo’s treatment and research. Barbara has worked at Mayo Clinic since 2007. She enjoys international travel and cooking.