Mito - Cascade and family testing
Overview
Relatives of a patient previously diagnosed with a specific mutation may be tested for the same mutation.
Testing depends upon the mutation type identified in the relative:
Nuclear DNA: cascade testing is via Sanger sequencing on an EDTA blood sample
mtDNA: cascade testing is via NGS panel for the specific mutation- blood, liver or muscle samples are suitable depending upon the condition.
Category
Cost
Nuclear DNA:
$340 (per variant)
$440 (per externally identified variant)
mtDNA:
$700 (per variant)
$800 (per externally identified variant)
Reporting time
6-8 weeks
Contacts
P: 1300 11 8247
E: [email protected]
Specimen Requirements
Nuclear DNA:
| Sample Type | Sample Volume |
|---|---|
| EDTA blood | Adult: 4ml; Child: 2ml |
| Saliva |
ORACollect kit |
mtDNA:
| Sample Type | Sample Volume |
|---|---|
| EDTA blood | Adult: 4ml; Child: 2ml |
| Saliva | ORACollect kit |
| Liver/Muscle | 1-5mg |
| Urine# (No longer recommended) |
10-20ml (early morning) |
#Urine is no longer recommended as the preferred sample type in adults >30 years. Our assay is able to detect variants, including the common MELAS m.3243A>G mutation, present at low levels in EDTA blood samples. Urine may still be sent but please note due to the critical collection, storage and transport requirements for urine (detailed below), assay failure rates may be higher compared with blood.
Important notes for specimen storage and handing:
- EDTA blood: Store at 4°C or room temperature. Do NOT freeze.
- Urine: Early morning collection, frozen fresh (store at -20°C/freezer if patient collected at home/clinic), transport to lab on dry ice. To be stored at -70°C if not extracted immediately.
- 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.