Chromosomal microarrays (CMAs) are an older and different type of genetic testing technology. CMAs look at the structure of your chromosomes to identify abnormal changes involving extra or missing pieces of DNA. It is a much less complete test than whole exome sequencing. For this reason, the chances that an individual with a neurodevelopmental condition will find receive get a result from a CMA test is only 15%-20%. In contrast to that, the same individuals are likely to find an answer ~30%-50% of the time using whole exome sequencing (see this publication). Hence, researchers are now advocating for the use of whole exome sequencing rather than CMAs as a first-tier diagnostic for children with neurodevelopmental conditions.
How is the test Different from a Chromosomal Microarray?
