ExonArrayDx – a novel, specialized service to evaluate one or more genes from a list of >460 genes for partial or full gene deletions or duplications defined at the exon level. The ExonArrayDx test is based on the use of a ultra-high resolution microarray-based comparative genomic hybridization (array CGH), which has a higher sensitivity for detecting deletions and duplications compared to MLPA and quantitative PCR (qPCR), to detect partial or complete gene deletions and duplications of clinically significant genes. GeneDx offers this service for disorders known to be caused by deletions or duplications within a single gene as well as for disorders due to haploinsufficiency or loss of function for a specific gene for which the frequency of gene deletions/duplications is currently not well established.
There are several categories of disorders for which the relevant genes are tested by ExonArrayDx:
- Autosomal dominant developmental disorders caused by haploinsufficiency
- Multiple congenital anomaly syndromes
- Inherited (familial) cancer and genome instability syndromes
- Autosomal recessive metabolic disorders
- X-linked mental retardation
- Autism spectrum disorders
- Inherited cardiac disorders
- Inherited eye disorders
It can be ordered for:
- Analysis of selected genes on our current test menu in which a deletion/duplication is suspected (Tests by Gene)
- As a second tier test on a specimen in which previous sequence analysis did not identify a disease-associated mutation.
Other possible indications for ExonArrayDx analysis include:
- As a primary test in a Mendelian disorder due to haploinsufficiency when sequence analysis fails to identify a causative mutation; in particular when whole or partial gene deletions are a known cause for the disorder (i.e., STK11 deletion associated with Peutz-Jeghers syndrome or RAI1 deletion associated with Smith-Magenis syndrome).
- To evaluate for deletions or duplications when a single mutation has been identified for a recessive disorder.*
- As a confirmation test for deletion or duplication detected by MLPA or qPCR.
- Carrier testing when a specific deletion or duplication has been identified in an affected relative (i.e., testing of carrier status of female relatives of an affected male with X-linked hydrocephalus due to L1CAM deletion).
Deletion/duplication analysis by ExonArrayDx may be requested for a single gene or for a custom panel of clinically related genes.
*GeneDx offers sequence analysis for a large number of autosomal recessive disorders. For most autosomal recessive disorders, if single gene sequencing is done at GeneDx and only one variant has been identified in a patient and if clinically indicated, GeneDx will also perform ExonArrayDx microarray analysis to exclude a deletion of the second allele at no extra cost. This does not apply for exome or genome sequencing, Xpanded panels and may not apply to other large multi-gene panels (please check individual information sheets for details). ExonArray Testing (Test codes, CPT codes and TATs)
Our standard specimen requirement for this analysis is a single tube with 1-5 ml blood in EDTA. Please DO NOT send buccal swabs/brushes. Please see our standard Sample Requirements page.