DNA, Gene and Genome

What is DNA?

Our bodies are made of trillions of cells. Inside each of those cells are chromosomes. In humans, we have 23 pairs of chromosomes. One chromosome of each pair comes from our mother (egg) and the other chromosome comes from our father (sperm). Each chromosome is composed of deoxyribonucleic acid (DNA). A simple analogy is that a person’s DNA serves as a blueprint for all of the information that makes us who we are. The DNA itself is organized into specific segments called genes, which encode proteins needed for our bodies to grow and function. The specific coding within the genes is composed through the use of only four specific DNA bases: A, T, G, and C.

What is genetic testing (genetic analysis or genome analysis)?

Genomic analysis is a test that extracts DNA from cells isolated from saliva, blood, or tissue and analyzes genes related to innate genetic characteristics and the development of specific diseases. Personalized health care can be provided through various test items by genetic company, such as metabolism, reaction and sensitivity to food, exercise effect, disease risk prediction, drug reaction speed and sensitivity, carrier of genetic disease, and innate personal tendencies and characteristics. This is a state-of-the-art healthcare program. There are types of tests that require you to see a doctor, and there are DTC types that you can test yourself at home.

Are all changes in DNA disease-causing?

No, some changes in DNA are normal variations between humans, which do not cause disease. These types of changes are called benign variants. Alternatively, some changes in the DNA can lead to damaged or faulty genes, which in turn can disrupt the function of the proteins normally encoded by the DNA. These changes are called deleterious or pathogenic mutations.

If I have done whole genome sequencing analysis, do I need to undergo periodic testing like a health checkup?

No. Genes do not change throughout life, so if you have taken the Whole Genome Analysis Test, there is no need to do it again. You only need to do it once in your life. However, as research analyzing diseases or characteristics using those genes continues, the results of analyzing them may vary depending on scientific developments. This means that new research results can lead to new predictions.

How does cancer develop?

Cancer develops due to an accumulation of damaging DNA changes (mutations) in a single cell over an individual’s lifetime. Most of these changes happen as part of the natural aging process that our bodies go through over time (called somatic changes), while in rare instances some individuals are born with a mutation in all of their cells (called germline changes), which gives them a “head-start” to developing cancer in their lifetime.

What is hereditary cancer?

There are three categories of cancer: (1) Sporadic, (2) Familial/Multifactorial, and (3) Hereditary.

(1)Sporadic cancer is generally thought to be due a combination of environmental factors and natural aging process.

(2)Familial/Multifactorial cancer generally refers to a history of cancer in families that cannot be attributed to a single gene mutation. Development of cancer in these families is likely due to a combination of mutations in multiple low risk or moderate risk cancer genes as well as environmental factors.

(3)Hereditary cancer refers to cancer that is due to a single gene mutation that significantly increases an individual’s risk of certain cancers over their lifetime. Individuals are born with these singe gene mutations, and in most cases, they have been passed down from family members (inherited )for a number of generations.

Will hereditary cancer testing tell me if I have cancer?

No, this type of testing cannot diagnose cancer or tell you if you will definitely develop cancer in the future. However, this test may provide valuable information on your risk to develop certain types of cancer. This information can be valuable for risk reduction and early detection, both of which are very important in fighting and/or preventing cancer.

What does a positive or negative result mean in genetic cancer test?

A positive result means that a change in the gene, called a mutation, was found that very likely explains an individual’s personal and/or family cancer history. Some genes have specific management guidelines already established to follow for patients that are found to carry a mutation; the guidelines may include increased surveillance, and risk-reducing surgical options and/or medications. Other genes require the consideration of family history in combination with other factors to create a specialized follow-up plan made with the assistance of a physician or genetic counselor.  A negative test result means that there was no mutation or variant detected in the genes tested. There are multiple reasons why this might occur. Patient has not inherited the known mutation that was previously found in a family member. This person would have cancer risks similar to the general population.

Who should get a disease prediction test?

(1) If a family member has cancer or a major disease and you want to know whether you are at high risk for the same disease,
(2) If you do not currently have any disease, but are concerned about a disease that may occur in the future and want to actively deal with it (group with high involvement in health management)
(3) If you are curious about whether your parents’ genetic disease will also occur in your children
(4) If you are curious about the reaction to a specific drug due to genetic predisposition
(5) If you have bad lifestyle habits, knowing your actual genetic risk may motivate you to change your bad lifestyle habits.

Do specific genes cause specific diseases?

 All humans have about 30,000 genes. A gene is a basic unit that regulates a protein and consists of thousands or tens of thousands of bases depending on the type. Many studies classify genes associated with specific diseases. Depending on the company, tens to hundreds of final representative genes are selected to calculate the risk of a specific disease. There are also genes that are highly correlated with certain diseases, such as BRCA or APOE. However, there are many other genes that actually affect dementia or breast cancer.

What is genetic markers or genotypes?

There are approximately 3.2 billion base sequences in human DNA, of which approximately 10 million have a different mutated base sequence for each person, and these differences contribute to the diversity of humanity and the differences between people in the development of quality. These different nucleotide sequence regions are called markers or SNPs (single nucleotide polynomials), and three groups of combinations, or genome types, are created depending on the combination of homologous chromosomes inherited from the father and mother, respectively. For example, if both parents are originally A and have a normal genetic combination, if a mutated gene (B) is received from one parent, and if both parents are mutated, there are three groups of genomes: AA, AB, and BB, respectively. The type is determined. The incidence of special diseases can be found for each group.

What is a carrier? How will this affect me and my children?

Some genetic diseases may be recessive. In other words, a disease occurs when a mutated gene (BB) is received from both parents. If you receive a normal gene on one side and a mutated gene on the other (AB), you can be healthy and not develop a disease, and this is called a carrier. If healthy carriers of a gene that causes a specific disease (AB . The purpose of Pre-Pregnancy Plannig Insight is to determine whether you have these specific rare diseases.

After taking a test, it was found that I had a high risk of developing certain diseases. What are the chances of that disease actually happening to you?

Genetic predisposition varies slightly depending on the disease. Even within the same cancer, some diseases have a greater genetic predisposition, while others have more important environmental factors. Therefore, genetic predisposition alone cannot explain all diseases. However, if other environmental factors are the same, it can be said that if a person has a high genetic predisposition, the probability of contracting a disease is higher. How to utilize this depends on the individual’s choice. It’s like when the weather forecast tells you the probability of rain tomorrow, each individual may feel the severity and importance of it differently and react differently. In general, when the genetic predisposition to a specific disease is high, it is necessary to proactively perform related checkups more frequently and make efforts to minimize environmental risk factors that can cause the disease.

A weighted value is given to the influence through multi-gene SNP, calculated using an algorithm, and the risk is expressed based on the ODD ratio. Even for the same disease, results may vary depending on the company and the bio-informatics technology (algorithm). The ODD ratio value starts from 1. This is because everyone is exposed to risk. The probability is averaged based on this value and expressed as a multiple of how high the risk is based on that value.

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