How Ordering the Right Chromosomal Microarray Analysis Can Help Your Patients

Differentiating Microarray Tests

Many believe that all arrays are the same and that there is no difference between ordering a chromosomal microarray analysis (CMA) from one lab or another. While hard to believe, this is not the case. Many factors can influence the quality of a CMA test, including the expertise and experience of the cytogenetics laboratory staff, how many CMAs the particular laboratory have reported to date, and the quality of the array itself. At Baylor Genetics, we were one of the first laboratories in the world to offer CMA tests in a clinical setting. Since launching our CMA test, BG has been able to analyze over 80,000 arrays. In addition, our comprehensive array has exon level coverage of over 4,200 genes. It also includes over 60,000 probes for SNP analysis, which is used to detect absence of heterozygosity (AOH) and uniparental disomy (UPD). It’s important to look at these factors and track record of a company when deciding which CMA test to order for a patient.

CMA Case Study 

To further put it into perspective, consider the following hypothetical example when choosing a CMA test. An infant with dysmorphism, developmental delay, and other medical issues is referred for genetic counseling. His pediatrician ordered an array from the cytogenetics department housed in the local hospital. Over the course of the next few years, the patient is seen by various hospital specialists including neurology and clinical genetics. After having a number of single gene and panel tests done, which all returned normal results, the decision was made to offer the patient a whole genome sequencing (WGS) test. The WGS includes a copy number variant analysis. During this test, a chromosomal abnormality was detected. The patient had a deletion and duplication, which should have been detected on the original array. Unfortunately, the first lab array failed to pick up the copy number loss and gain. They were small and below the threshold for detection of the first lab. If a high-quality array test was ordered in the first place, the patient would have had a diagnosis ending his diagnostic odyssey years earlier. In addition, the family would have been better off because all of the tests after the initial array would have been redundant, thus saving the family time and a lot of money. By choosing the right CMA test and company, physicians can get closer to finding the right diagnosis and move forward with medical management earlier on.

More About CMA

Chromosomal microarray analysis (CMA) provides comprehensive genetic testing for the most common chromosomal conditions as well as a large number of severe genetic conditions not detected by traditional chromosome analysis. This test explores chromosomes in detail to help detect genetic conditions that cause significant disabilities. Baylor Genetics evaluates the entire human genome for regions that contain too many or too few copies of genetic material. As mentioned above, BG is one of the leading genetic companies in microarray analysis. Our most comprehensive CMA test (TC 8665) has the maximum sensitivity for detection of gains and losses and physicians can expect results within 14 days of the sample being received. 

This first-tier diagnostic test is recommended by the American College of Medical Genetics (ACMG), the American Academy of Neurology (AAN), the Child Neurology Society (CNS), the American Academy of Pediatrics (AAP), and the International Standard Cytogenomic Array (ISCA) Consortium. CMA should be considered for individuals who lack a sufficient specific history or features on physical examination to suggest a specific genetic (or non-genetic) cause for intellectual disability, developmental delay, autism spectrum disorder, or multiple congenital anomalies.

For more information regarding our CMA test, please visit

Why Baylor Genetics?

Improving healthcare is at the core of who we are at BG. Through continuous innovation and research, our team is equipped to provide physicians the best results for their patients. We are able to diagnose rare diseases and disorders because of our existing large-scale, high-throughput capabilities and our CLIA-certified, CAP–accredited laboratory.

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