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The Environment and Human Health

Author(s): Nancy P. Moreno, PhD

Gene Variations Affect Susceptibility

Many diseases are the outcome of a complex inter-relationship between multiple genetic and environmental factors. Research suggests that individual susceptibility to a given disease is influenced more by certain genes than by exposure to environmental agents. The Environmental Genome Project, for example, is working to characterize how certain human genetic variations contribute to the likelihood that a given individual will be susceptible to an environmentally induced disease.

Each person has two copies of genetic material, or genes—one set from each parent. Genes are specific sequences of bases that encode instructions for making proteins. Changes in one or both copies of a gene can confer greater or less susceptibility to harm from an environmental exposure. 

Toxins in the environment can trigger development of disease. In addition, combinations of the effects of several to many genes determine whether a person actually will become ill. Age, gender, and dose and timing of exposures also influence the development of diseases with an environmental component. 

Some chemicals, radiation and even infectious agents, such as viruses, can cause gene mutations (permanent changes in the DNA sequence) that affect cell function. Sometimes, these mutations lead to the development of various kinds of cancer over time.

Many researchers are working to identify groups of genes that confer protection and/or greater risk of harmful effects from environmental exposures.

Funded by the following grant(s)