National Organization for Rare Disorder (2015), xeroderma pigmentosum also known as XP is a group of rare inherited skin disorders that is regarded as a reaction to sunlight (photosensitivity) with skin blistering that occur after exposure from the sun. This rare disease is a result of mutation in genes that are involved in DNA replication or repair. UV rays from the sun and toxic chemicals can damage the DNA. DNA replication and normal cells usually will fix those damage DNA, but with xerorderma pigmentation, the DNA is not repaired. The POHL gene safeguards cells when DNA is damaged from UV rays. Mutation of POHL gene can cause XP. Likewise, mutations of the XPC, ERCC2, or HRAD30 gene have been identified in XP. HRAD30 (DNA polymerase eta gene) that enables error-free cellular replication by avoiding UV induced damage (National Rare Disorder, 2015). Nucleotide excision repair (NER) plays a key role in DNA-repair when it comes to xeroderma pigmentosum disease. The proteins produced by NER recognize damaged DNA, excise the abnormal section and replaces it with correct DNA (Genetics Home Reference, 2015).In addition, the early signs of XP is acute sunburn, photosensitivity, and persistent redness or erythema of the skin. This also includes freckle like spots on the skin and predisposition to skin cancer (Pierce, 2013). Skin abnormalities can be seen in XP such as: hyperpigmentation, hypopigmentation, excessive scarring, and skin lesions (telangiectasias). Affected children with XP will have severe sunburn after few minutes in the sun, then that sunburn will turn into blisters that will lasts for weeks. People affected by xeroderma pigmentosum have an increased risk of skin cancer. In other cases, dwarfism, delayed development, mental retardation, and neurological impairment may occur in xeroderma pigmentosum.
The relationship between xeroderma pigmentosum and mutation was discovered when the genes responsible for DNA repair is impaired. DNA repair normally reject many mutations that arises in XP. Research findings discovered that the cells with defective DNA repair are likely to retain mutation than a normal cell; this also includes mutations in genes that regulate cell division (Pierce, 2013). Due to the mutation of the POLH, XPC, and ERCC2 genes, the DNA that was damaged from the sun and toxic chemicals are not repaired. This as a result will lead to cell malfunction and ultimately will become a cancerous.
In addition, DNA replication is controlled by cell cycle. The cell cycle is necessary for the cells to grow, replicate DNA, and divide (Noelle, 2015). Without the DNA replication the cells cannot divide and cell cycle cannot progress. DNA replications are necessary for replacing dead or damaged cells that cause diseases. Mutation can impact the role of DNA replication and repair. A mutation caused by damaging effects of chemicals, UV-rays, or radiation will cause an error DNA replication. Damaged DNA replication can lead to many diseases or cancer, because damaged cells are not replaced.
Understanding how transcription and translation can be complex. According to Pierce (2013), transcription is the process where all cellular RNAs are synthesized from DNA template and translation is the process of translating the sequence of mRNA during protein synthesis. Mutation can affect transcription and translation, because it changes the genetic sequence and and protein structure. Mutation affects transcription because it changes the amino acid sequence and destroys the protein function. Likewise, mutation affects translation because it intervenes the process of mRNA translation and the cellular components that control them (Scheper, Van der Knaap, & Proud, 2007) . As a result, disorders arises when mutations alters the transcription and translation process. Likewise, xeroderma pigmentation is a result of mutation in genes that are responsible for repairing the damaged cells (Genetic Home Reference, 2015). In normal cells, the DNA that is damaged by toxic chemicals and UV rays are fixed before it causes problems. This is not the case for XP; build up of unrepaired damaged cells can lead to the symptoms of xeroderma pigmentosum
Today, genetic technology has the potential to alter human species. Genetic engineering is a type of technology used to change the genetic makeup of cells. It is a technique that manipulates genetic material by artificially adding genes or specific traits from one organism and inserted into a plant or animal resulting to transferring of traits. Although, gene therapy is still on the experimental stage in XP, using viral vectors (adenoviruses and retroviruses) are being studied to carry gene replacement products by administering it in the vitro of animals (Hafeez & Williams, 2015). Another research that I read that are being studied for genetic therapy is figuring out how to transfer the polymerase gene into XP. Evidence suggest that polymerase has the ability to repair DNA in tissues and could have implications for research into aging and degenerative diseases (Tenenbaum, 1999). In the future, knowing how damaged DNA replicates itself can improve better treatment and diagnosis of XP.
In conclusion, I am thankful to have learned another disease like xeroderma pigmentosus. Never did it occur in my head that there is a disease like XP. I realized the importance of genetic replication, translation, and transcription process to prevent many diseases or disorders. Although mutation does not necessarily cause problems; however, in many instances mutations can be dangerous because they are responsible for many diseases or genetic conditions like xeroderma pigmentosum. Genetic engineering can play an important role to learn more about the disease and find a treatment plan of many diseases. This assignment was definitely a great learning experience for me because now I have a better understanding of xeroderma pigmentosum.