Overview

Respiratory chain enzyme testing in biopsies or perimortem samples of muscle, liver or heart or in cultured skin fibroblasts has traditionally been the first line diagnostic method used for most children with suspected mitochondrial disease.

An accurate enzyme diagnosis can guide subsequent testing of single genes or to confirm that mutations in a candidate gene are truly causative. In recent years it has become common to offer exome sequencing or mtDNA sequencing or both prior to enzyme testing.

Enzyme testing is now used more commonly as a second line test for functional validation of candidate genetic variants from genomic studies or when those genomic studies fail to identify a candidate disease gene.

Category

Cost

Price dependent on sample type:

Sample Type Cost

Skel. Muscle

$1130

Liver, cardiac muscle

$1130
*Cell lines $1525

*Skin fibroblast and transformed lymphoblast cells lines are suitable only in certain circumstances.

Reporting time

Reporting time dependent on sample type:

Sample Type Reporting Time

Skel. Muscle

6 weeks

Liver, cardiac muscle

6 weeks

*Cell lines 6 months

*Skin fibroblast and transformed lymphoblast cells lines are suitable only in certain circumstances.

Contacts

P: 1300 11 8247
E: [email protected]

Specimen Requirements

Specimen requirements dependent on sample type:

Sample Type Sample Volume

Skel. Muscle

50mg (tissue)

Liver, cardiac muscle

20mg (tissue)

*Cell lines 25sq.cm flask

*Skin fibroblast and transformed lymphoblast cells lines are suitable only in certain circumstances.

Important notes for specimen storage and handing:

  1. Cultured cells: Store at room temperature. Do NOT freeze.
  2. Tissue biopsy/autopsy samples: Must be stored at -70°C (-20°C is inadequate) until transport on dry ice. Once frozen, they must not be allowed to thaw.
  • Postmortem Samples: COLLECT AS SOON AFTER DEATH AS POSSIBLE, preferably within 2 hours. Note the time between death and freezing of samples.
  • Liver and muscle tissue samples should be no larger than 1.0 cm cubes; heart, kidney & brain samples may also be collected.
  • Enzymes can be assayed in postmortem heart but endomyocardial microbiopsies are too small.

Notes

Please provide the following clinical details (if available) to enable optimal interpretation:

  • Patient name, medical record no., date of birth, date of sample, delay between death and freezing if relevant.
  • Full clinical summary and family history with pedigree.
  • Include copies of relevant investigations
    • urine organic & amino acids
    • tissue histology (including electron microscopy & enzyme histochemistry)
    • summary of CT, MRI or MRS studies of brain.
  • Paired plasma lactate & pyruvate levels; multiple estimations preferred.
  • Paired CSF lactate & pyruvate levels, preferably with blood levels obtained at about the same time.