Sunday, 18 November 2007

What is the genetic test?

A genetic test is a test that involves the analysis of chromosomes, genes and/or gene products (e.g. proteins or enzymes) to determine whether a genetic alteration related to a specific disease or condition is present.

(Secretary's Advisory Committee on Genetic Testing, 2002.)

What is the difference between genetic screening and genetic testing?
Genetic screening is used when your patient:
-Has no signs or symptoms
-Has no clinically significant family history
-Belongs to a certain population (such as a racial or ethnic group) that may be at greater risk for certain disorders or traits.
Genetic screening is not diagnostic; further testing is needed to confirm, make or predict the diagnosis of a condition. Examples of genetic screening are: newborn screening for phenylketonuria and carrier screening for Tay-Sachs disease and (although not currently the standard of care) population screening for hereditary hemochromatosis.

Genetic testing is used when your patient has:
-Clinically significant signs and/or symptoms
-A clinically significant family history
-Positive genetic screen results
Genetic testing can diagnose or predict the likelihood of a genetic condition. Examples of genetic testing are: diagnostic testing for Fragile X syndrome in a child with mental retardation, prenatal diagnostic testing for Down syndrome by amniocentesis, and presymptomatic testing for Huntington disease in an individual with a family history of HD.

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