CHROMOSOME ARRAY (aCGH), POSTNATAL
Pseudonyms: Microarray, Chromosomal Microarray, CMA, Constitutional Array, Array Comparative Genomic Hybridization, Array CGH, Whole Genome Array
TURNAROUND TIME: 14 days
TESTING METHODOLOGY: Array Comparative Genomic Hybridization
- Collect: 3-5 mL peripheral blood in EDTA (purple) and 3-5 mL peripheral blood in sodium heparin (green) for children and adults; 2 mL EDTA and 2 mL sodium heparin for newborns
- Min. Collection: 2 mL EDTA and 2 mL sodium heparin for children and adults; 1 mL EDTA and 1 mL sodium heparin for newborns
- Transport: peripheral blood in EDTA (purple) and sodium heparin (green) at 20-25oC
- Stability: Ambient: 24 hours; Refrigerated: 72 hours; Frozen: unacceptable
- Unacceptable Conditions: Frozen or clotted specimens; specimens in anticoagulants other than EDTA and sodium heparin
A Cytogenetics Laboratory Test Requisition must accompany the specimen. Contact the Cytogenetics Laboratory at 918-502-1722 to obtain further information.
Test Summary: Test can detect copy number variations (gains and losses) throughout the genome. The array covers almost 1,000 gene regions important in development and over 245 recognized genetic syndromes. The array has a minimum average resolution of 35 kilobases across the entire genome. In addition, there is a higher resolution coverage of approximately 10 kilobases in the targeted regions. These include regions involved in common microdeletion and micoduplication syndromes, genes associated with Mendelian disorders and the subtelomeric and pericentromeric regions of the chromosomes.
Methods: Microarray analysis using an array of 135,000 oligonucleotide probes; abnormalities are confirmed by fluorescence in situ hybridization (FISH)
Interpretation: An abnormal (clinically significant) result is reported when an abnormality (gain or loss) is associated with a known Mendelian disorder, a recognized microdeletion or microduplication syndrome or an unbalanced chromosome rearrangement. The results of this test may also be of unclear clinical significance. In these cases, studies of parents may be required to assist in interpreting the results. Carrier status for autosomal recessive conditions is not reported unless the variation detected is consistent with the patient's reason for referral. Consultation with a genetic professional is recommended for test interpretation.
Test Limitations: Balanced chromosomal rearrangements (reciprocal translocations, Robertsonian translocations, inversions and balanced insertions) and imbalances of regions not represented on the microarray will not be detected. This microarray is not designed to detect mosaicism. A normal result does not exclude the diagnosis of any of the disorders represented on the microarray since the percentage of patients who will demonstrate an alteration varies depending on the locus.
Test Variables: Turnaround time will average approximately 28 days if confirmation of an abnormality by FISH is necessary.
FDA Approval: This test is not approved by the FDA and it should used as an adjunct to other clinical information.
Indications for Use:
- 1st tier postnatal test for patients with multiple congenital abnormalities, developmental delay or intellectual disability and autism spectrum disorders
- Follow-up test for patients with a previously normal standard chromosome analysis and multiple congenital abnormalities, developmental delay or intellectual disability or autism spectrum disorders
- Test to determine whether patients with apparently balanced chromosomal rearrangements actually have cryptic unbalanced rearrangements
- Test to determine gene content and size of chromosome abnormalities previously identified by standard chromosome analysis or FISH studies