In this era of healthcare evolution, the field of genomics has gained a lot of popularity. The first human genome was sequenced in 2003 and, since then, the curiosity for genetic testing has led us to explore deeper. Our medical fortunes are revealed by our genes. Genetic testing potentiates the possibility of preventing various medical disorders right from infancy to adulthood. Hence, it is not surprising that Americans have already spent more than 5 billion dollars on it.
All You Need to Know About Genes and Gene Testing
Our cells contain 46 chromosomes that pack deoxyribonucleic acid (DNA) molecules in them. These chromosomes are arranged in 23 pairs, one pair of sex chromosomes and 22 pairs called autosomes. Genes, made up of DNA, are placed on these chromosomes. Each gene is responsible for different characteristics in our unique physical make up such as height, eye color, dental structure, etc. Every chromosome is packed with thousands of genes, and the total number of genes is termed as a genome. Each individual differs from another because of his or her distinct gene structure.
Gene testing is done to assess changes in one’s gene and chromosome from normal. The tests look for various gene mutations, missing genes, or an extra gene. Different types of gene tests are available, such as:
- Molecular gene tests – These tests look for a specific gene mutation and identify a missing or an added gene. The limitation for this test is that it can pick up mutations only for certain disease conditions and fails to identify multiple mutations in a gene.
- Chromosomal tests – These tests look for alterations in structure, assembly, and number of chromosomes that could lead to genetic conditions, for example, an extra chromosome represents a condition called Down’s syndrome. A method called karyotyping is used to determine the number and structure of chromosomes.
- Biochemical tests – These tests assess the activities of proteins present in each gene and are mainly useful in newborn screening.
Genetic testing helps one determine the possibilities of developing a genetic disorder in future. It also identifies if a person suffers from a genetic disorder based on his or her symptoms. It helps couples planning for pregnancy by providing information about the chances of their passing a genetic disorder to their offspring.
Helpful or harmful?
- Gene testing will not determine your destiny. Except for a few very rare diseases like sickle cell anemia or Huntington’s disease, most diseases arise from multiple gene mutations. Genetic predisposition determines that we can potentially develop illnesses like arthritis, diabetes, or cardiac ailments, but our environment determines the actual chances of development and progression of the illnesses. These environmental factors comprise the lifestyle, stress, diet, sleep habits, and so on. Thus, we cannot predict with a 100% accuracy that every individual who has inherited the BRCA1 gene mutation will develop breast cancer at some point in life.
- Either tests results are interpreted by professionals, or it is left to individuals to search for answers on the internet. It can be emotionally challenging for individuals to know their own risk for developing a disease condition and professionals are usually genetic counselors who are not trained in diagnosing and advising treatment protocols. In addition, there is an actual dearth of welltrained genetic counseling professionals.
- A gene testing before pregnancy is highly encouraged so that couples can use the information received and plan their next move if needed. This allays the emotional pressure involved with pregnancy. In addition, it prepares them for the outcome or allows them to opt for other alternatives such as IUI or adoption.
- One very important concern with gene testing is the way an individual handles the information received after the tests. The individual can either be optimistic and make the necessary lifestyle changes knowing that they are vulnerable to an illness or they can become traumatized with the news, which could have a deleterious effect on their quality of life. Many people do not want to know whether they will or will not suffer from any particular illness.
- Genetic tests are useful in reaching certain therapeutic decisions, for example, in cases of cancer, the decision of whether or not to start the patient on tamoxifen is made based on the presence of a certain enzyme detected by gene testing.
- Bridging privacy is another worry for people, as the laws of privacy do not fully extend to long-term care insurance companies. Although privacy is assured regarding information, it does not allay the client’s fears.
Genetic testing is a whole new world. Not everyone is optimistic about getting to know diseases that might cross their path someday. Nor do parents seek to produce designer offsprings. Loss of privacy, inadequate data, and lack of proper information regarding diseases such as diabetes or cardiovascular illnesses are some more added concerns regarding gene testing. However, gene testing might be helpful in diagnosing certain illnesses and also in detecting serious conditions such as Down’s syndrome during pregnancy. In addition, doing a gene test does not cost a lot of money.
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. National Association of Health Underwriters. NAHU Position on Genetic Testing. October 6, 2005.
. Khoury MJ. Genetics and genomics in practice: the continuum from genetic disease to genetic information in health and disease. Genet Med 2003;
. Burke W, Motulsky AG. Hypertension. In: King RA, Rotter JI, Mikulski AG, editors. Genetic basis of common diseases. 1992.