Chromosomal Aberrations

Identification of individual chromosomes remained difficult until advances in staining techniques such as Q-banding revealed the structural organization of chromosomes. The patterns of bands were found to be specific for individual chromosomes and hence allowed scientists to distinguish the different chromosomes. Also, such banding patterns made it possible to recognize that structural abnormalities or aberrations were associated with specific genetic syndromes. Chromosome disorders, or abnormalities of even a minute segment (or band) are now known to be the basis for a large number of genetic diseases.

Chromosomal disorders and their relationship to health and disease are studied using the methods of cytogenetics. Cytogenetic analysis is now an integral diagnostic procedure in prenatal diagnosis. It is also utilized in the evaluation of patients with mental retardation, multiple birth defects, and abnormal sexual development, and in some cases of infertility or multiple miscarriages. Cytogenetic analysis is also useful in the study and treatment of cancer patients and individuals with hematologic disorders. The types of chromosomal abnormalities that can be detected by cytogenetics are numerical aberrations, translocations, duplications, deletions, and inversions.