Chromosomal micro-array analysis, or CMA, is an advanced genetic test that allows the diagnosis of more than 100 genetic disorders that cause intellectual disabilities and autism.
CMA is an improved version of CGH testing, also known as biochip tests. This test not only detects missing or excess genetic material but can also show the location of the specific defect to help diagnose different disorders.
The CMA test is used as part of prenatal genetic screening, as well as the diagnosis of children with intellectual impairment. It is considered one of the most advanced genetic tests available today. It is preformed in most genetic clinics as part of prenatal genetic screening for diagnosis of many genetic disorders.
One of this test’s biggest advantages is its fast results: these are typically given after as soon as 10 – 14 days.
When is the test needed?
CMA tests are preformed in cases of a risk for genetic defects, to identify the genetic disorder in the DNA segment.
The test can be performed as part of prenatal screening, or for detecting the genetic basis of developmental impairment in children. Since CMA can identify the source of genetic defects, it is used mostly in cases where the source of the disorder is unclear, or when finding the location of a defect in the genetic material is required.
Healthcare providers use this test in the following cases:
Diagnosing specific disorders:
children with intellectual impairment or developmental delays often suffer from different syndromes caused by genetic defects. CMA testing can help place the defect on the genetic sequence and diagnose the disorder.
In addition, when development abnormalities are detected during the pregnancy (such as during anatomy scans or fetal wellbeing scans), it is important to undergo a CMA test to evaluate the prognosis and help the parents understand the future outcome of their fetus’ genetic disorder.
Moreover, since each genetic disorder ultimately manifests slightly differently in each patient, knowing the disorders better can help healthcare professionals improve their work process to better accommodate their patients’ needs. When genetic defects are diagnosed, parents may also wish to perform further genetic screening tests before future pregnancies, use PGD and prepare for the future.
Identifying new disorders:
In addition to the diagnosis of existing disorders, CMA analysis can be used in research to identify and characterize new genetic disorders. Doctors and researchers can use this test to match clinical findings to specific genetic disorders, and vice versa. This way, they can expand current understanding of genetic disorders and understand new disorders.
Who should take the test?
Like biochip testing (CGH), CMA tests are recommended in the following cases:
Following amniocentesis or CVS – CMA can be used in cases of a risk of fetal development abnormalities, as part of prenatal screening. The test is recommended in cases of slow fetal growth or different birth defects, or in cases of a risk of genetic disorders.
Children with developmental delay or intellectual disabilities – CMA is recommended as part of the genetic analysis of developmental disabilities, autism and intellectual impairment in children, to give a better understanding of the genetic disorder causing these conditions.
How does the test work?
CMA testing works in a similar way to biochip testing. It is performed in DNA samples taken via amniocentesis (in prenatal testing) or a blood test (in children). The genetic samples go through hybridization using fluorescent dye, after being mixed with a healthy DNA sample.
After the fluorescent dye is applied, molecular technologies are applied to help place the genetic sequence.
Next, the genetic material is mixed with a healthy DNA sample. Based on changes in the fluorescent dye, geneticists can detect the specific locations with missing or excessive genetic material. This helps identify genetic disorders and diagnose them more efficiently.
What diseases can the test identify?
CMA tests can detect many genetic diseases, such as Down’s syndrome. It can also detect rarer disorders that are difficult to identify with other tests. CMA helps identifying known genetic diseases and even understand new diseases. For these reasons, it is recommended in all cases of a risk or suspicion for genetic disorders.
