Basic concepts of medical genetics, pathogenetics, part 3

Abstract

The genetic material controls life activities of the cell through regulating the synthesis of proteins which directly mediate these activities. Regulatory genes, in addition, control the transcription of many classes of small RNAs that have fundamental roles in direct and feed-back regulation of most aspects of the genetic material [1]. Mutations cause structural alterations of the genetic material. Depending on the site, nature, magnitude and effects of the mutational event as well as on the functions and importance of the mutated genes, pathogenetic mechanisms that result in deficient synthesis of gene products, synthesis of defective gene products or disturbed regulation of cellular activities will lead to the development of genetic disorders, secondary to the ensuing pathophysiological alterations of cellular functions. Maintaining the stability, integrity and species-specific identity of the genome represents a prerequisite, not only for executing cell functions properly, but more fundamentally for the beginning, continuation and conservation of life. It is the preservation of the collaborative and integrated intimate relationship of these three aspects of the genome that represent the real kernel and true essence of existence of all forms of life. Many pathogenetic mechanisms that drastically affect genome stability and genome integrity have been defined. These particular groups of mutations constitute important detrimental events that act via different pathways, e.g. defective genetic re-