الفهرس 
Introduction and Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Nowadys there IS increasing aWaI:eness of the importance of genetic factors in the aetiology and pathogenesis of many disorders affecting man. Perhaps of more importance is that this knowledge has also led to possible means of prevention of such disorders through genetic counselling and antenatal diagnosis [Macleod et al., 1987] the new genetics has provided penetrating insights to common diseases such as cancer, diabets aIld
atherosclerosis [Cotran R. S. et al., 1994] .
Genetic abnonnalities are a common cause of disease handicap and
death among infants and children as about 1 % of all newborn infants possess
gross chromosomal abnormalities, an additional 0.5% have an inborn error of metabolism or an abnonnality of the sex chromosomes. [Baired, 1988] .
The relation between genetic and cancer is associated to the two types of genes which distinctive and apparently casual changes in cancer . Oncogenes and oncosuppressor genes [Macsween N. M. & Whaley K. 1992] . Genetic disoders are classified into three categories : (l) Those related to mutant gel1es of large effect e.g. all Mendellian disorders, (2) Disorders with multifactorial (polygonic) inheritance e.g. hypertension & diabetes, and (3) chromosomal disorders. [Cotran R. S. et al., 1994] .
Genetic markers have a definite role in family shldies, distribution of genes in population and also in forensic medicine such as in problems of disputed patenlity also affect the process of transplantation as a donor tissue is more likely to be accepted if it is anti genetically identical or as closely matched as possible [Abdel-Salam E., 1990] .