Chromosome Microarray testing; CMA testing
The microarray most commonly gives a negative result which means that there are no missing pieces or additional pieces of DNA. If the microarray test does find that there is either missing or additional DNA (called copy number variants) the next step is to assess the significance of the results.
Not all missing or additional pieces of DNA cause problems. Some can be present in a person or multiple members of a family without causing any problems at all. The genetics specialists interpreting the test will look at the case reports to see if the changes found are known to be associated with the problems the patient is having. They will also take into consideration the genes known to be located within the copy number variant segment that has been found. In many cases the same results have been seen previously in other patients and the test result will allow the doctors to make a diagnosis. However, sometimes the significance of the changes found is unknown. This happens quite often because the human genome is enormous (it contains three billion base pairs) so there are many places for variations to occur. If a copy number variant of unknown significance is found, the parents of the child can be tested. If one of them has an identical variant in their DNA but does not have the medical problems found in the child, the variant is less likely to be the cause of the child’s problems.
What does the microarray not test for?
There are several common conditions that will not be detected on the microarray test. These include:
Last Review Date: November 1, 2019