Trends in Molecular Medicine
ForumGenetic testing for disease susceptibilities: consequences for genetic counseling
Section snippets
Mendelian disorders
In Mendelian disorders, a disease-causing mutation in a single gene has high penetrance, producing an observable, often profound effect on phenotype. Commonly, the manifestations are not amenable to environmental manipulation and thus are untreatable. Affected individuals are ascertained because of overt symptoms or signs, or a family history. For a family, the social consequences of having a relative with a Mendelian disorder can be enormous: revelation of one member's genetic status can have
Common complex disease susceptibilities
Common complex disorders are presumed to result from the additive effect of mutations of low penetrance at multiple loci. Although when occurring individually these mutations may have no phenotypic effect, when acting in concert, and in the presence of environmental stimuli, these mutations may produce disease or increase the risk of disease. In this model mutations are regarded as ‘predisposing’ mutations because they are necessary to disease causation but not sufficient. Genetic testing for
Genetic counseling versus predispositional testing?
The fundamental difference between these two models is that the Mendelian disease model uses genetic testing to modify the assessment of disease risk in high-risk individuals most often for personal decision-making. By contrast, the complex disease model uses genetic testing to identify increased risk in low-risk individuals for the purpose of instituting interventions to modify risk for future disease.
Do the Mendelian model with predominance of genetic influences and the complex disease model
Concluding remarks
Will genetic counseling vanish when predispositional testing becomes the norm in the primary practitioner's office, as risk modification becomes the primary reason to seek health care? Definitely not. Gene discovery, through which our understanding of common complex diseases will flourish, will also continue to expand our understanding of hundreds if not thousands of rare Mendelian disorders. Novel knowledge of disease causation will enable more accurate diagnosis and create more demand among
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Cited by (13)
(ii) Family-based linkage and case control association studies
2008, Current OrthopaedicsCitation Excerpt :Risk-conferring genes, exposure to environmental factors and interaction between these important determinants are required in the development of complex diseases. On the other hand, Mendelian diseases refer to simpler forms of diseases, wherein alteration or mutation at a single gene is sufficient for manifestation of disease.11,12 Before establishing the genetic component of a disease, which is a requirement for gene mapping, it is important to first estimate the effect of its genetic factors.
Genetics
2015, The Growing Spine: Management of Spinal Disorders in Young Children, Second EditionCounseling customers: Emerging roles for genetic counselors in the direct-to-consumer genetic testing market
2013, Journal of Genetic Counseling"Is it really worth it to get tested?": Primary care patients' impressions of predictive SNP testing for colon cancer
2013, Journal of Genetic CounselingBridging the communication divide: A role for health psychology in the genomic era
2012, Professional Psychology: Research and PracticeGenetic testing and common disorders in a public health framework: How to assess relevance and possibilities
2011, European Journal of Human Genetics