Abstract

Chromosomal abnormalities are able to produce genetic instability, which is the main cause of many diseases. Cytogenetics is analysis of any kind of chromosomal abnormalities. Chromosomal alterations can be divided into structural and numerical abnormalities, both of which play a significant role in the development of many diseases, particularly cancer. Today, most cytogenetic analyzes are performed by traditional methods (such as karyotype, banding and micronuclei testing) as well as modern techniques (such as M-FISH, SKY, and CGH). The factors causing chromosomal abnormalities can be classified into both external and internal groups. External factors that play an important role in causing anomalies in war can be classified into two physical (including different types of rays) and chemical agents. In this review, we explain a general model for development of chromosome abnormalities with emphasis on the method of production of abnormalities using chemical agents. According to this general model, each phase of DNA replication can convert any existing abnormalities to a higher degree of abnormality. This general theory can also be employed for chemicals, according to which chemicals producing chromosomal abnormalities can be classified into two main groups of non-delayed and delayed chemicals in terms of their effects. Non-delayed chemicals consist of gaps and breaks and delayed chemicals cause chromatid changes. Finally, some common types of chemicals used in military wars (including Agent Orange, depleted uranium, and mustard gas), with its cytogenetic effects and chromosomal aberrations caused by them, are discussed. © 2019 Baqiyatallah University of Medical Sciences. All rights reserved.