Genetic Testing :: Genetics Disorders Diseases Papers

Genetic Testing Genetic screening uses a variety of laboratory procedures to find out if a person has a genetic condition or disorder or is likely to develop a disease based on his or her genetic makeup. Individuals may wish to be tested if the family shows a history of one specific disease such as Huntington's Disease or breast cancer, if they show symptoms of a genetic disorder which could be improved by early diagnosis, or if they are planning a family and are concerned about the possibility of passing on a genetic trait to their offspring. This last type of screening can look at the parent's genotype or look at the genotype of the fetus or newborn. This type of screening can also look for a specific disorder or can be done as a general test for common disorders as in prenatal testing or more commonly newborn screening. Genetic tests use techniques to examine genes or markers near the genes. Direct testing for diseases such as Cystic Fibrosis and Sickle Cell Anemia come from an analysis of an individual's specific genes. A technique called linkage analysis, or indirect testing, is used when the gene cannot be directly identified but can be located within a specific region of a chromosome. This testing requires additional DNA from an affected family member for comparison. Because each person's DNA is unique (except for identical twins), genetic tests also can be used for individual identification ("DNA fingerprinting"). This technique is often used in forensic work, where samples from a crime scene such as blood or semen could be used as incriminating or acquitting evidence. Genetic testing is a complex process, and the results depend both on reliable laboratory procedures and an accurate translation of results. Tests also vary in sensitivity, that is, their ability to detect mutations or to detect all patients who have or will develop the disease. Interpretation of test results are often complex even for trained physicians and other health care specialists. Types of Genetic Testing Carrier Identification includes genetic tests used by couples whose families have a history of recessive genetic disorders and who are considering having children. Three common tests include those for cystic fibrosis, Tay-Sachs disease, and sickle-cell trait but more tests are coming on the market at a very high rate. Norman Frost of the University of Wisconsin Madison Medical School says, "Potential new genetic tests roll off the conveyor belt of the human genome project almost once a week " (2).