Exam Questions and Answers on the Genetic Diseases - Paper Example

Question: Breast cancer is a complex disease that is as a result of an interplay of several genetic and environmental factors whose pathophysiology is not well understood. It is also known to have a hereditary component. Due to the serious public health problem that breast cancer poses, scientists have embarked on a journey to determine the factors that contribute to the development of breast cancer. The aim is to understand the cause hence come up with formidable preventive measures. Therefore, genetic screening for breast cancer is not prognostic or diagnostic because the gene might be present even in the absence of disease. Thus, genetic screening for breast cancer, just like any other multifactorial disease, is only used to inform about the risk of developing the disease.

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Scientists have identified two breast cancer genes, namely BRCA1 AND BRCA2, as the susceptibility genes. These genes produce tumor suppressor proteins which are useful in repairing damaged DNA; but upon mutation of any of these genes, the protein product is not made, or it is malfunctioned which may lead to unrepaired DNA genes causing cancer. Results of studies indicate that germline mutations in these genes can be attributed to a significant number of breast cancer cases. A deleterious mutation in BRCA1 or BRCA2 nay is inherited from either of the parents. However, this does not imply that every child who inherits these mutations will develop breast cancer. In fact, the chance of developing breast cancer in people who have inherited the cancer genes is approximately 75%. This is because although mutations in these genes are the most significant risk factors, other risk factors such as environment, lifestyle and other biological factors play a role in the development of the disease. Other research findings also suggest that breast cancer susceptibility is also a product of other genes that are highly penetrant genes whose isolation is ongoing.

Question: Development of genetic testing for genetic diseases has been impactful in screening, diagnosis, and prognosis of diseases such as Huntingtons disease, Cystic fibrosis and Tay-Sachs disease. Genetic testing is mostly used in screening of newborns for such diseases to aid in early interventions for prevention of illness or at least reduce its severity. Genetic testing also used in carrier testing to determine whether parents possess recessive genes of diseases such as sickle cell anemia and the risk of passing the genes to their offspring. Carrier testing is mostly performed if the parents have a family history of a particular hereditary disease or if their ethnic group has a higher risk of developing the disease. Prenatal diagnostic testing is also done to identify changes in the genes or chromosomes of a fetus if the couple is at an increased risk of having a baby with a genetic disease. In instances where a presumptive diagnosis of a genetic disease has been made through clinical history, symptoms and physical examination, genetic testing might be used to confirm the diagnosis.

The major types of genetic testing that are available include biochemical, cytogenetic and molecular testing. In cytogenetic testing, the genetic disease is detected by examining whole chromosomes from a culture of white blood cells or other tissues. For instance, diseases such as leukemia are diagnosed genetically by observing abnormalities in chromosomes of cultured bone marrow cells. On the other hand, biochemical testing entails analyzing samples for protein changes that may have resulted from the suspected genetic alterations. This means measuring the activity of enzymes, the quantity of the protein or the level of metabolites of an enzyme. For example, Hex-A concentrations in a patients blood can be measured to determine whether they are carriers. For minute DNA mutations, direct DNA tests are recommended. DNA testing involves amplifying the targeted DNA using Polymerase Chain Reaction (PCR) and sequencing the DNA to detect the mutations that may be connected to the disease. An example of a disease diagnosed through DNA testing is cystic fibrosis.

Question: Dr. Wagner, a bone marrow transplant specialist, used Pre-implantation genetic diagnosis (PGD) and assisted reproductive techniques (ARD) at University of Minnesota to treat Molly Nash, a daughter of Jack and Lisa Nash. In the process, they were able to have another kid without Fanconi anemia which leads to leukemia in the before the child reaches ten years of age. The procedure required them to produce several embryos through in vitro fertilization. Then the embryos were tested for genes that predispose to Fanconi anemia. HLA-typing was also done to ensure they matched with Mollys HLA so that the transplant would not be rejected.

Producing an embryo that is a perfect HLA match, free of Fanconi anemia genes and capable of initiating a successful pregnancy is disheartening. Lisa Nash produced several eggs and endured miscarriages before success came along. After a series of failed conceptions, hormonal replacement therapy was administered in another ARD clinic where she became pregnant with the only one successful match. She was confined to bed to prevent miscarriage. Adam Nash was born after 52 hours of labor after the mother resisted C-section which would have led to a loss of a lot of cord blood that they needed to treat Molly.

In October 2000, a bone marrow transplants hospital for children with Fanconi anemia known as Fairview- University Hospital in Minneapolis, transferred tissue obtained from Adams umbilical cord into Mollys body successfully. Although the transplant did not cure Mollys Fanconi anemia, it prevented the progression to leukemia. This has helped her live a normal life although she is likely to suffer from other complications of Fanconi anemia such as cancer of the mouth and neck later in life. Adam, on the other hand, did save not only his sister's life but also fulfilled his parents wish for another baby that is free of Fanconi.

Question: From most people, you will hear them say cancer is a genetic disease. It means that the condition occurs as a result of gene variations and changes. The mutations in the Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) in the genetic formations of the human body result in the derangements of the healthy body cells growth thus causing the disease. Regarding the statement that cancer is a genetic disease, the statement should not at any point be confused with the disease being hereditary.

In several rare cases of the disease, such the breast cancer, a slight number of people which is 10-15 percentage of the breast cancer might be hereditary. However, many cancer cases are genetic which means that the disease can result from abnormal functions of a gene or even more genes. Most people tend to perceive the transmission of cancer within the families as a single cancer gene, but its basis is the genetic changes.

Having the inherited genetic variations with the disease, it does not mean one will develop cancer. These genetic differences affect an individual lifestyle, and most of the people with the inherited gene are in a bigger position of developing the disease however they can have a better lifestyle which can prevent the gene mutation like avoiding smoking, alcohol among other triggers.

Question: The immunity system of humans relies on the genes. The genes in the human cells ensure that the body stays immune. Regarding inheritance of genes, most or all newborns inherit several genes that are only responsible for providing the production of the immune system composition. It is critical to ensuring that the child gets protection against several infections to the human body. The babies may acquire the components from the mother from breastfeeding and also through the placenta. These variations affect the children in relations to the lifestyle of mostly the mother during the pregnancy period and the lactation period.

Moreover, the inheritance attainment can occur through the creation of recurrent infections caused by defects in the antibody functions transmitted from a component of the immune system which can mutate and cause damage to factors like the lymphocytes. However, some people have the ability to resist genetic diseases. The resistance or immunity to the diseases might be hereditary. The immunity attainment happens through different ways regarding the diseases. In most cases, acquired resistance is one of the many ways.

The presence of a particular antibody, give several attributes into the reactivity of many antibody forming cells. The cells formed can include specific cells that are needed for immunity adaptability and can include phagocytic cells and lymphoid cells that form concerning the antigens. They are also passively transferred. Immunity is acquired through the placenta, whereby the fetus gets a maternal antibody and as a result may develop to establish natural immunity.