Chromosome Analysis
Specialist scientists called cytogeneticists examine a person's chromosomes for defects. Usually, they will analyse the chromosomes in the white cells (lymphocytes) in a person's blood. They can also analyse the chromosomes found in the cells of other body tissues like bone marrow or skin.The cell samples have first to be grown under special laboratory conditions and this can be very time-consuming. This is one reason why it can take several weeks for the results of a chromosome analysis to be reported. Cytogeneticists will use special chemicals to stop the cells they are examining at an appropriate stage when the chromosomes are at their most compact. At this stage, called METAPHASE, the chromosomes can be stained with different dyes. The stain used most often is called GIEMSA in a technique producing G-BANDED chromosomes. Different stains give the chromosomes a characteristic pattern of light and dark bands which helps with their identification.
Sometimes the chromosomes are analysed when they are a little less compact so that more bands can be seen and smaller extra or missing pieces of DNA can be identified. This is called High Resolution Analysis.
Chromosomal micro-array: This is more extensive a test then a normal karyotype of the chromosomes and therefore can show micro-deletions.
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