Genetic Health Information and the Human Genome Project - Assignment Example

Genetic Health Information Q1. The Human Genome Project (HGP) is a scientific research project that aims at identifying the sequence of chemical bases found in the human DNA. Its objectives were set by a National Research Council report issued in 1988 in USA. It has long been believed that diseases tend to run in families. Studies have shown that close relatives have a shared risk of contracting particular diseases that had affected a family member earlier. Virtually every disease has a genetic component, even the most common diseases such as cancer. The aim of the HGP is to find out the thread of DNA present in our body cells (Palladino2006, p. 4). The genetic code found in our DNA, has many potential insights for individual resistances and susceptibilities to diseases. The HGP is quite distinct from other biomedical research because it has been defined by a series of very quantifiable and concrete goals. For example, it has been used to construct physical and genetic maps. These maps have been used as vital research tools and have proved to be invaluable in determining more than 100 genes involved in diseases such as achondroplasia, breast cancer, colon cancer, and Huntington disease. HGP has simplified the human genetic code as well as animals and plants in a four-letter alphabet. These chemical constituents of each DNA molecule are A (adenine), C (cytosine), G (guanine) and T (thymine). The project has been able to explain that there are 23 pairs of chromosomes in each human cell, and each contains millions of these nucleotides. Through the project, it has been proved that there are 3 billion nucleotides. Studies on these chromosomes have been used clinically to explain to expectant mothers if they are going to give birth to a baby boy or girl. HGP has led to improved techniques of genetic screening for various diseases before birth. A genetic library has been created. This library contains genetic information of relatively homogeneous regions in human DNA. Therefore, individuals do not have considerable variability at this locus. If it is found out that a genetic disease is produced from a specific allele or mutation being present, screening can be done to identify who the individuals are. It is now possible to determine the chances that a child might inherit genetic disorders associated with parents by analyzing the parental gamete DNA. This has allowed genetic disorders to be corrected before birth. Research is also being carried on rapid selection and insertion of DNA into human individuals; these may soon lead to reproduction of “designer” children. HGP has also led to performance of genetic tests that determine mutations at certain loci that make people susceptible to environmentally induced diseases. Therefore, such individuals receive advice on how to prevent the diseases by avoiding the environment that causes the disorder. Researchers have also been able to determine the molecular processes that maintain human bodies in good working order. These studies have also revealed how these processes are disturbed during illness. The discovery of each gene that affects an illness now reveals about how that illness arises. The study of the human genome has also been used in predicting individuals’ responsiveness to certain drugs because variations in drug response often arise from genetic differences. For example, individuals metabolize drugs at different rates. This study has made prescription of drugs a much more individualized affair. New and efficient ways of analyzing the effects of drugs such as blocking or stimulating certain genetic pathways are now in play. Q2. Deoxyribonucleic acid (DNA) is a chemical molecule that has the biological instructions that make each organism unique. It contains instructions needed by an organism to reproduce, survive and develop. During reproduction, DNA together with the instructions it contains is passed from parents to their offspring. DNA is tightly packed in the cell nucleus. DNA undergoes replication where it unwinds for it to be copied (Palladino, 2006, p.12). DNA also unwinds during transcription so that its instructions may be used to make proteins for biological processes. DNA is made up of chemical building blocks known as nucleotides. The nucleotides include; adenine (A), guanine (G), cytosine (C), and thymine (T). They are made up of three parts, that is, phosphate group, nitrogen base and sugar moiety. The sequence of these bases gives the biological instructions in a DNA strand. For example, the sequence ATGCTA might instruct for brown eyes while TCGCA might instruct blue eyes. On the other hand, a chromosome is an organized package made up of DNA found in the nucleus of the cell. Different species have a different chromosome number. For example, humans have 23 pairs of chromosomes. Of this, 22 pairs of chromosomes are autosomes while the other pair is a sex chromosome of X and Y. During reproduction each parent contributes one chromosome, so that the offspring gets half of their chromosomes from their father and half from the mother. The gene is the basic physical unit used in inheritance. They are passed from parents to offspring and have the information required to specify traits. They are arranged one after the other in chromosomes. An allele is a version of a gene. Individuals inherit two alleles for each gene, each from a parent. If two alleles are identical, the individual is said to be homozygous. If they are different, the individual is heterozygous. An allele is not only a variation among genes, but also a variation among non-coding DNA sequences. A mutation is a change in a DNA sequence. It occurs whenever there is a change in the genetic information of an organism, due to different reasons. Mutations can be either point mutations or frameshift mutations. Point mutations only make a single change in a single codon while everything else is undisturbed. Point mutations are divided into silent mutation, missense mutation and nonsense mutation. Frameshift mutations alter the entire reading frame of the DNA. Frameshift mutations are divided into insertion and deletion. Q3. Nurses use the advances made in genetics for health-care provision by making interventions that they use to detect, treat, prevent, and manage conditions that are genetic in nature. They have used genetics in various applications such as; Identifying Single-Gene Disorder- Nurses use the knowledge and skills in genetics in determining these disorders and patients who may be affected. They discuss the implications and possibilities, and refer appropriate specialist services. Nurses provide counseling and record information that patients need later when they make decisions about disease prevention and reproduction. By providing this medical care, they have managed to reduce the risk of common diseases such as heart disease, colorectal cancer, breast and ovarian cancer that develop due to single-gene disorders. Multifactorial diseases- Diseases such as hypertension, coronary heart disease, rheumatoid arthritis, and diabetes are determined by multiple genes where each has a small effect in increasing risk. They also develop as a result of environmental factors such as diet and smoking. These diseases have a high prevalence. Hence, nurses are involved in identifying at-risk patients and provide advice on relevant preventive measures such as lifestyle modification, screening, and drug therapies. Nurses also advise patients on whether to take tests such as a paternity test to interpret the results and discuss genetic risk. Antenatal care- Nurses can now detect a variety of genetic disorders such as Down’s syndrome, Duchenne muscular dystrophy, and cystic fibrosis through prenatal testing. Some women even prefer discussing concerns about genetic issues with their midwives rather than Genetic Professionals. Therefore, nurses need to be approachable and armed with facts on genetics. Nurses also address areas such as family history and help women to consider taking up antenatal screening such as that for hemoglobinopathies and Down’s syndrome. Q4. Genetic and genetic science is redefining the understanding of human health and illness. It is, therefore, essential to recognize genomics as a core science for health professional knowledge. Studies have proved that most diseases and conditions have a genomic component; this has increased care when dealing with genetic information on the pathways of screening, prevention, diagnosis, prognosis, and selective treatment. The public also expects that a registered nurse, genetic information when providing care. This has raised the need for nurses to demonstrate proficiency when dealing with genetic and genomic information in their practice. For example, Nurses need to understand the genomic and genetic basis of health or illness for which the patient is seeking care. They also need to understand the variables that impact their response. Nurses should be competent enough to recognize a newborn at risk for mortality and morbidity due to genetic metabolism errors. They should be ready to identify a couple that is at risk of having a child with a genetic disorder. They should promote informed consent that involves risks, limitations, and benefits of participation in genetic research. Facilitate drug selection or dosage in the treatment of a patient with cancer-based on molecular markers. Nurses should also assist anyone having questions related to genomic and genetic information or services. Q5. Chromosomal abnormalities usually manifest due to the change in chromosome structure or number. There are several types of these chromosome abnormalities; however, they are divided into two major groups, that is, numerical abnormalities and structural abnormalities. Numerical abnormalities: This arises when a person is missing a single chromosome from a pair, resulting to a condition known as monosomy, or when an individual has more than two chromosomes of a certain pair, this condition is called trisomy (Palladino 2006, p.28). There are different genetic conditions that arise from numeric abnormalities. For example, Down’s syndrome, also known as Trisomy 21. This condition occurs when an individual has three copies of chromosome 21 instead of two pairs. Turner syndrome is another example of a genetic condition. It manifests when a person, in this case a female, is born having only one sex chromosome (the X chromosome). Structural Abnormalities: They manifest when the chromosome number changes. This can be due to several reasons. For example, it can be deletion where a part of a chromosome is missing. Structural abnormalities can also be due to duplication where a portion of a chromosome is doubled resulting in extra genetic information. It can also be due to translocation whereby a portion of a chromosome is transferred to another chromosome. There are two classes of the translocations, that is, reciprocal translocation, where portions from different chromosomes are exchanged and Robertsonian where the entire chromosome structure binds to another centromere. Inversions and rings are other causes of structural abnormalities. Mostly, structural abnormalities arise due to an incident in the ova or sperm. Therefore, every cell of the body bears the anomaly. Some abnormalities occur during conception and lead to mosaicism where only a section of cells has the anomaly. Single Gene Mutations: These are disorders that arise due to an anomaly in a single gene. They are divided into recessive, dominant, X-linked, and autosomal disorders. A recessive mutation manifests when both alleles of an organism are mutant, that is, the individual should be homozygous for the mutant allele to show the phenotype. These variations make the affected gene inactive leading to a loss in function. Examples of recessive diseases include spinal muscular atrophy, cystic fibrosis and phenylketonuria. Dominant mutations manifest only when the individual is heterozygous for a certain trait, where one allele is normal and the other one is mutant. Normally, dominant mutations lead to a gain in function causing an increase in the activity of a given gene. Examples of dominant diseases are variegate porphyria, Myotonic dystrophy and Huntington’s disease. X-linked mutations arise when a gene is carried by the X chromosome. These mutations can either be dominant or recessive. Some of the disorders that arise due to dominant X-linked mutation include; Rett syndrome, Fragile-X syndrome and Goltz syndrome. Mitochondrial inheritance- Mitochondria are inherited from maternal ova only. Therefore, a pattern of inheritance may develop where alterations in the mitochondrial DNA generate a condition that affects both males and females. Infected males do not pass on this condition to his children and therefore all his children are unaffected. Some of the disorders related to mitochondrial inheritance include Leigh’s disease, Leber’s hereditary optic neuropathy (LHON), Wolff-Parkinson’s- White syndrome and mitochondrial myopathy. Complex or Multi-factorial inheritance- These are disorders that arise due to the combination of mutation in multiple genes and environmental factors. Some of the diseases that are due to this inheritance are; Alzheimer’s disease, diabetes, cancer, obesity, heart disease, and high blood pressure. Q6. Direct DNA testing method is carried out when a sample that is, DNA, RNA or protein is examined to find out whether or not the individual has a certain genotype, mostly a pathogenic mutation in a certain gene. Direct testing is mostly done using PCR. It can be used to detect Fragile X or myotonic dystrophy mutations (Palladino, 2006, p.39). Biochemical tests are studies done to identify the body’s enzymatic defects. These tests can be used to determine enzymatic disorders such as porphyria, phenylketonuria, and glycogen-storage disease. This can be easily explained to a patient as a test that focuses to see if the body is performing its activities appropriately by identifying if the activities are very fast or slow. Cytogenetic tests- These are techniques where small DNA fragments are isolated, and copied to generate unlimited amounts of cloned material. They are used in diagnosis of conditions such as sickle cell anemia, cystic fibrosis, Huntington’s disease, and hemochromatosis. To a patient this can be explained as experiments that are done to find out whether their DNA is functioning properly or not. This may be due to deletion, addition or inversion of a portion of the DNA. Q7. A) The genetic principle that a nurse should apply here is that she should have knowledge on the risks, limitations, and benefits of breast cancer and explain it clearly to the patient. B) The nurse should explain to Sally and her family on the importance of carrying out a genetic test. After convincing them, she should perform a mitochondrial DNA test since this condition lies mostly among the ladies in her family. Earlier diagnosis of breast cancer will enhance provision of better and efficient care to Sally. Q8. Genetic conditions have more than one identifying features or symptoms that have very distinct features. First, a child can be born with distinct body deformities; an example is achondroplasia where a baby has limbs that are smaller than usual. An individual may also have abnormal organ function such as the heart, brain, gut or kidney. Another sign of a genetic disorder is neurological problems, for example, when a baby is unable to nurse or bottle feed or when the baby’s body is floppy. Infertility is also a common syndrome, especially in Klinefelter’s syndrome where boys may have smaller testes, growth of breast, less facial body, and reduced muscle tone. Q9. The human cytochrome P450 plays a vital role in metabolism of 90% of the drugs. It may undergo genetic variation that may lead to up-regulation or down-regulation of enzymes. This will in turn determine the rate at which warfarin is metabolized. If there is up-regulation of enzymes it then means that warfarin will be metabolized quickly and therefore the patient dosage should be increased for therapeutic effects to be obtained. However if there is down-regulation of enzymes, warfarin will be metabolized slowly and this may be harmful to the patient. The dosage should then be decreased for the patient’s safety. References Palladino, M. A. (2006). Understanding the human genome project. San Francisco: Pearson/Benjamin Cummings Read More