skip navigation
A B C D E F G H I J K L M N O P Q

Test Identifier Information

 
Registration CodeCTGN
Method

High density array comparative genomic hybridization (aCGH) provides a genome-wide analysis of DNA copy number variants (CNVs), with targeted probe coverage in disease-associated regions. For further technical details about the method and platform design see technical summary information. The microarray can detect microduplications and microdeletions around 100 times smaller than seen by conventional G-band chromosome analysis (karyotype). The inclusion of single nucleotide polymorphism (SNP) probes in the microarray design enables the detection of large regions of homozygosity, which can indicate uniparental disomy or recessive disorder.  

Results are reported as: 

      1. No clinically relevant copy number variant 

      2. Copy number variant of uncertain or unknown significance

      3. Clinically significant (pathogenic) copy number variant

      4. Clinically significant homozygosity, indicative of UPD

Parental specimens may be required to determine pathogenicity, mode of inheritance and/or recurrence risk. Please see separate test guide entry for parental follow up of microarray testing.

Diagnostic Use / Indications

Indications for testing include: intellectual disability, developmental delay, autistic spectrum disorder, seizures, failure to thrive, congenital anomalies and dysmorphism, short stature (but not ?Turner syndrome).

Cytogenetic microarray can also be used to diagnose any human genetic disorder resulting from copy number change, when the corresponding region of interest is represented on the array.

 

Constituent TestsGenomic DNA Extraction ;
External Price$880.85(Exclusive of GST)
  

Specimen Collection

 
Pre-Testing Requirements

Appropriate counselling and consent to testing prior to requesting this test. Consult with a clinical geneticist should be considered.

Urgent requests - phone the laboratory on 03 364 1425 

Please complete a patient consent form before requesting this test. 

Specimen Collection Protocols
  1. This test needs fresh, whole blood cells. The specimen must be well mixed.
  2. Do NOT centrifuge or freeze the blood tubes and keep at ambient temperature.
  3. Genomic DNA is extracted from the specimen prior to testing. This incurs an additional charge. Laboratories may submit DNA for testing, although it is not preferred. Please provide a minimum of 2 micrograms of DNA at 200 nanograms/microlitre.

 

Patient SpecimenAdult: 3-4mL EDTA + optional 1mL lithium heparin
Paediatric Specimen1-2mL EDTA + optional 0.5mL lithium heparin
Sample Delivery to Lab Same day or overnight courier, ambient
  

CHLabs Laboratory

 
DepartmentHaematology - Cytogenetics
Contact Details Email Email
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Contact Phone Number03 364 1425
Test Availability9am-5pm Monday to Friday
Turnaround TimeRoutine: 28 days, Neonate/urgent: 10 days; Family follow-up: 6 weeks
Interpretation

Multiple databases and current literature from NCBI are used to determine the clinical significance of the any copy number variants (CNV) identified by the cytogenetics microarray. Associations between the patient phenotype and the gene content/function of the affected region(s), or the known syndrome inferred, are also necessary to link pathogenicity.  

Limitations: Cytogenetic microarray will not detect balanced rearrangements, very small imbalances, mosaicism <20%, regions of homozygosity <5Mb, and some  uniparental disomy. The screening resolution of this test is approximately 40 kb in known clinically significant regions and 160kb elsewhere in the genome. Only imbalances of clinical significance, or unclear significance >200 kb, will be reported. Imbalances considered to be benign, based on available information at time of reporting, will not be reported.

Delphic Number Test Number8046

CHL Follow us on Facebook