Genes that permit or prevent infections

In addition to heritable immunodeficiencies and polygenic susceptibility, acquisition genes and resistance genes are important genetic determinants of infectious diseases. Normal forms of acquisition genes permit entry of microorganisms into cells; mutations prevent entry. Normal forms of resistance genes prevent infections; mutations permit infections. The Genome Project has resulted in a growing list of each type. The current lists support important clinical principles. Many, if not most, pathogens readily enter cells unless prevented by antisepsis, blocking, and sterile techniques. Many, if not most, infections occur primarily in persons with heritable mutations of resistance genes.