A chromosomal microarray analysis, also called microarray or array, is a type of genetic test that looks for missing or extra portions of a chromosome. We call these “deletions” or “duplications.” In this section, we explain how a microarray analysis works and the different types of results.
A chromosomal microarray analysis, also called microarray or array, is a type of genetic test that looks for missing or extra portions of a chromosome, that we call “deletions” or “duplications.” These regions may include one or multiple genes.
Some types of microarrays can also detect regions on the chromosomes that are identical on both copies. This type of region is called a “region of homozygosity” and may lead to clues as to what genes may be causing your child’s features.
Microarrays are utilized frequently for people with developmental delay, autism spectrum disorder, or many other structural and functional organ differences or birth defects. The types of genetic changes identifiable in a microarray are different than those identified by gene sequencing. Sometimes a person might get a microarray and a gene sequencing test at the same time.
There are various results that can be obtained from a microarray.
A positive result means that a genetic test identified a change in a gene that we are confident causes the features in you or your child. Another word that you may see on a report to describe a positive result is “pathogenic”.
A likely positive result means that a genetic test identified a change in a gene that is suspected to cause the clinical findings in you or your child, but there may not be enough scientific information known at this time to say it is definitively positive.
A negative result means that there were no gene changes identified by the testing method that could explain your or your child’s clinical findings.
A variant of unknown clinical significance is a genetic change that, based on the currently available scientific knowledge, cannot be interpreted as pathogenic or negative.
In the future, scientists are likely to discover what these variants of unknown clinical significance mean. Until then, receiving results with a variant of unknown clinical significance can be understandably frustrating as we can’t interpret what the DNA change means for your child or family.
Keep in mind, genetic testing does not always find an explanation for medical symptoms.
The absence of a positive genetic testing result does not take away an individual’s clinical diagnosis.
Also, a non-diagnostic genetic testing result does not mean that the condition is not genetic. Instead it may mean that the testing completed was not able to identify a genetic cause at this time