Introduction
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.CMA is used to determine if there are chromosomal imbalances, either large (whole extra or missing chromosomes, also detected by standard karyotype) or detect small (chromosomal alterations such as micro-deletions and micro-duplications) genetic information, also called copy number variation. CMA is an emerging molecular detection technology in the field of prenatal diagnosis. This approach can accurately detect structural chromosomal abnormalities.
Microarray data analysis is the final step in reading and processing data produced by a microarray chip. Samples undergo various processes including purification and scanning using the microchip, which then produces a large amount of data that requires processing and software.
Testing Indication
- CMA testing is often recommended in multiple abnormalities which are not specific to a genetic syndrome.
- CMA is increasingly utilized for genetic testing of individuals with unexplained developmental delay (DD)/ intellectual disability (ID), autism spectrum disorders (ASD), or multiple congenital anomalies (MCA).
- Prenatal CMA is recommended for a patient with a fetus with one or more major structural abnormalities identified on ultra-sonographic examination and who is undergoing invasive prenatal diagnosis.
- If a woman considers her risk high enough to have invasive testing, CMA testing should be considered for any pregnancy for which traditional karyotyping would be offered.
Testing Benefit
- Microarray is a new powerful tool for studying the molecular basis of interactions on a scale that is impossible using conventional analysis. This technique makes it possible to examine the expression of thousands of genes simultaneously.
- A newer genetic technology in the prenatal setting, CMA is a method of measuring gains and losses of DNA throughout the human genome.
- CMA may be especially useful when other tests have failed to yield a diagnosis, such as unexplained seizure disorder, growth delay, psychiatric illness, neuro-muscular conditions.
- Microarray analysis is more likely to provide a genetic diagnosis, primarily because of its success with nonviable tissue, and is especially valuable in analyses of stillbirths with congenital anomalies or in cases in which karyotype results cannot be obtained.
Sample Required for testing:
Whole Blood - 4-5ml in EDTA (purple capped tube)
- The microarray analysis is also performed on amniotic fluid (30ml) and CVS sample for the prenatal testing confirmation collected in sterile tubes.