Genetic epidemiology

Genetic epidemiology is the study of the role of genetic factors in determining health and disease in families and in populations, and the interplay of such genetic factors with environmental factors. In slightly more formal language, genetic epidemiology was defined by Morton as "a science which deals with the etiology, distribution, and control of disease in groups of relatives and with inherited causes of disease in populations". [cite book | last=Morton |first= N. E. |year=1982 | title=Outline of Genetic Epidemiology |publisher=Karger| city= New York| isbn=380552269X ] It is closely allied to both molecular epidemiology and statistical genetics, but these overlapping fields each have distinct emphases, societies and journals.

Traditionally, the study of the role of genetic in disease progresses through the following study designs, each answering a slightly different question: [cite web |url= http://www.dorak.info/epi/genetepi.html |title=Introduction to Genetic Epidemiology] | author= M. Tevfik Dorak | date=2008-03-03| accessdate=2008-03-04]

* Familial aggregation studies: Is there a genetic component to the disease, and what are the relative contributions of genes and environment?
* Segregation studies: What is the pattern of inheritance of the disease (e.g. dominant or recessive)?
* Linkage studies: On which part of which chromosome is the disease gene located?
* Association studies: Which allele of which gene is associated with the disease?

This traditional approach has proved highly successful in identifying monogenic disorders and locating the genes responsible.

More recently, the scope of genetic epidemiology has expanded to include common diseases for which many genes each play make a smaller contribution (polygenic, multifactorial or multigenic disorders). This has developed rapidly in the first decade of the 21st century following completion of the Human Genome Project, as advances in genotyping technology and associated reductions in cost has made it feasible to conduct large-scale genome-wide association studies that genotype many thousands of single nucleotide polymorphisms in thousands of individuals. These have lead to the discovery of many genetic polymorphisms that influence the risk of developing many common diseases.

References

Further reading

*cite book
author = Khoury, M.J.
coauthors = Beaty, T.H.; Cohen, B.H.
year = 1993
title = Fundamentals of genetic epidemiology
publisher = Oxford University Press | city=New York
isbn = 0195052889
*citation| title=Human Genome Epidemiology: A scientific foundation for using genetic information to improve health and prevent disease | editor1-first=Muin J. | editor1-last=Khoury | editor2-first=Julian| editor2-last=Little | editor3-first=Wylie |editor3-last=Burke| publisher=Oxford University Press | year=2003 | isbn = 978-0-19-514674-5 | url=http://www.oup.com/uk/catalogue/?ci=9780195146745
*cite book | doi=10.1002/0470011815.b2a05034 | chapter=Genetic Epidemiology | title=Encyclopedia of Biostatistics |publisher=Wiley Interscience| first=M. A. | last=Spence | year=2005
*cite book
last= Thomas | first=D.C.
year = 2004
title = Statistical Methods in Genetic Epidemiology
publisher = Oxford University Press
isbn=019515939X | url=http://www.oup.com/uk/catalogue/?ci=9780195159394

External links

* [http://www3.interscience.wiley.com/journal/35841/home "Genetic Epidemiology" (journal)]
* [http://www.geneticepi.org/ International Genetic Epidemiology Society]