Genetics and environmental medicine
by Bo Lambert
Introduction
01 Cancer
02 Ozone
03 Urban air
04 Air pollutants
05 Blue-green algae
06 Water mutagens
07 Contamination
08 Chernobyl
09 Radon
10 Medical geology
11 Renal hazards
12 Organohalogens
13 Estrogens
14 Food hazards
15 Mycotoxins
16 Poisoning
17 Genetics
18 Risk
(Excerpt from Chapter 17)
Genetic and environmental factors in human disease. |
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The roles of genetics
Traditionally, the genetic basis of disease has played a minor role in environmental medicine. This may seem surprising in view of the wellknown interactions between genes and environment in biological evolution and individual adaptation. Furthermore, during the last several decades, developments in molecular and genetic epidemiology have provided increasing evidence of gene-environment interactions in the etiology of many common disorders.
Genes determine the structure and level of proteins which regulate growth and metabolism, and environmental factors continuously modulate these activities. Each individual has a unique set of genes which constitute the individual genotype. The genotype variation is due to the random assortment of parental genes before conception, and the existence of many variant genes, so called polymorphisms, in the gene pool of the population. Environmental influences also display great variation due to differences in e.g. climate, cultural and living habits, and specific exposures. The phenotype, i.e. the sum of morphological and functional characters of cells and individuals, is the result of interactions between environment and genotype.
One aspect of the phenotype is the health of an individual, which is maintained by a delicate balance between environmental influences and genetic functions. Because each individual is genetically unique, the capacity to maintain health under various environmental conditions differs between individuals. Likewise, the risk of developing disease in response to environmental exposures will depend on this genetic individuality. Interactions between environmental factors and polymorphic genes contribute to the development of many complex diseases, e.g. diabetes, coronary heart disease and cancer. However, who gets sick may be greatly influenced by the genotype; individuals with a given genetic predisposition may be at increased risk of developing a particular disease if the exposure to a specific environmental factor exceeds a certain threshold.
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Professor Bo Lambert got his research education in molecular genetics and became a doctor of medicine in 1972. Following twelve years as a research fellow and associate professor in the Department of Clinical Genetics at the Karolinska Hospital, he was appointed professor of genetic toxicology in 1984, and professor of environmental medicine at Karolinska Institutet in 1991. His current research activities are in the fields of human cytogenetics, molecular mechanisms of mutagenesis, genetic effects of chemicals and radiation, and genomic instability. He has served as the president of the Nordic Environmental Mutagen Society, and as a member of the National Toxicology Council and the Research Board of the Swedish Cancer Society.
