Cytogenetics involves the examination of chromosomes to identify structural and numerical abnormalities. Chromosomes of a dividing human cell can be analyzed clearly from the sample collected from various sources:
Peripheral Venous Blood
Following few days of cell culture, chromosomes are fixed, spread on microscope slides, and stained. The staining methods for routine analysis allows each of the chromosomes to be individually identified. The distinct bands of each chromosome revealed by staining allow for analysis of the chromosomal structure.
There are different types of chromosomal studies offered, such as:
Karyotyping (Analysis of all 46 chromosomes for anomalies)
A way of viewing the entire genome of an individual. It can visualize individual cells and individual chromosomes. The study can microscopically look for abnormalities such as loss or gain of entire chromosomes, translocations of all or part of an arm of one chromosome to another or more subtle changes in banding patterns associated with various genetic syndromes.
Fluorescent In Situ Hybridization ( FISH )
Involves the hybridization of fluorescently labeled specific DNA sequence probes with patient DNA, and the subsequent microscopic detection of the presence, absence, abnormal copy number, or pathological location of a given fluorescence signal. The availability of specific locus probes for many known genetic defects has greatly increased the accuracy of detection of microdeletion and duplication syndromes.