Review Paper On Xeroderma Pigmentosum Beaches, wind-surfing, and other outdoor activities such as building sand castle, are what people think of doing when it comes to Summer. People go sun bathing on beaches, or use tanning beds to get nice tan on their skin For a certain group of people, just getting out of the house is very difficult for them. For these people, being exposed to the sun means another step closer to death Building sand castle surely is not an option. This very rare disease that is responsible for this unpleasant reaction is called Xeroderma Pigmentosum, known as XP in short. Despite the fact that it only occurs 1 in 250,000 people, the effects of this disease is remarkably severe People who suffer from Xeroderma Pigmentosum have to deal with many symptoms, for example skin disorders. One of the most common features of this disease is the severe sunburn after a short sun exposure. At birth, the individuals skin is healthy but after a while it will soon be damaged even with minimal sun exposure. The sunburn may last longer than what it normally 2, during a child s firstsun exposure, and can be very significant sign for the se of should, sometimes even weeks. This incident most likely occurs before the age of parents to question whether the child might be suffering from this disease. Other than irregular sunburn, a lot of freckles can be developed at a very early age Patients suffering from XP may also have irregular dark spots, excessive dryness, scaly skin, and limited growth of hair on chest and legs Other than skin abnormalities, 80 percent of XP patients might show symptoms of eye abnormalities. The patients might feel pain from the eyes when exposed to the sunlight. Even a small ray of light can produce discomfort feelings such as irritation to a patient. There may also be an inflammation of the eyelids, called blepharitis, and also an inflammation of the cornea, known as keratits Although neurological disorders occur only 30 percent for XP patients, but the effects are greatly serious. Most of XP patients who have neurological disorders usually experience loss of hearing, especially in high frequency. Other than losing the sense of hearing, XP patients may have to deal with one or more of the following symptoms, such as seizures, poor co-ordination, development of mental retardation, and decreases of reflex responses. Because Xeroderma Pigmentosum is an autosomal recessive disease, to obtain this disease, the individual will have to inherit two copies of the mutated gene, one from the father, and one from the mother. Therefore, if the individual only inherits one XP gene, this will only make that person a carrier, and the individual will not be affected physically by this disease. However the gene from the carrier can be passed to the next generation Every normal human being has a unit in the body that has the responsibility to repair the damaged dNA. dna is very significant to life because it is a chain of genetic information in each living cell. Its stability and integrity are very important Not a lot of people know this, but the rate of damaged dna is about 1,000 to 1,000,000 molecular lesions per cell per day. It may sounds a lot, but it is only about 0.000165%of the human genome. Damages to the dNa can be caused by two main factors, one if due to the environmental factor, and the other is due to the normal metabolic processes inside the cell. When dna is being repair properly, everything runs smoothly inside our body. However when the dna is damaged and is unrepaired, there could be many problems
Review Paper On Xeroderma Pigmentosum Beaches, wind-surfing, and other outdoor activities such as building sand castle, are what people think of doing when it comes to Summer. People go sunbathing on beaches, or use tanning beds to get nice tan on their skin. For a certain group of people, just getting out of the house is very difficult for them. For these people, being exposed to the sun means another step closer to death. Building sand castle surely is not an option. This very rare disease that is responsible for this unpleasant reaction is called Xeroderma Pigmentosum, known as XP in short. Despite the fact that it only occurs 1 in 250,000 people, the effects of this disease is remarkably severe. People who suffer from Xeroderma Pigmentosum have to deal with many symptoms, for example skin disorders. One of the most common features of this disease is the severe sunburn after a short sun exposure. At birth, the individual’s skin is healthy, but after a while it will soon be damaged even with minimal sun exposure. The sunburn may last longer than what it normally should, sometimes even weeks. This incident most likely occurs before the age of 2, during a child’s first sun exposure, and can be very significant sign for the parents to question whether the child might be suffering from this disease. Other than irregular sunburn, a lot of freckles can be developed at a very early age. Patients suffering from XP may also have irregular dark spots, excessive dryness, scaly skin, and limited growth of hair on chest and legs. Other than skin abnormalities, 80 percent of XP patients might show symptoms of eye abnormalities. The patients might feel pain from the eyes when exposed to the sunlight. Even a small ray of light can produce discomfort feelings such as irritation to a patient. There may also be an inflammation of the eyelids, called blepharitis, and also an inflammation of the cornea, known as keratits. Although neurological disorders occur only 30 percent for XP patients, but the effects are greatly serious. Most of XP patients who have neurological disorders usually experience loss of hearing, especially in high frequency. Other than losing the sense of hearing, XP patients may have to deal with one or more of the following symptoms, such as seizures, poor co-ordination, development of mental retardation, and decreases of reflex responses. Because Xeroderma Pigmentosum is an autosomal recessive disease, to obtain this disease, the individual will have to inherit two copies of the mutated gene, one from the father, and one from the mother. Therefore, if the individual only inherits one XP gene, this will only make that person a carrier, and the individual will not be affected physically by this disease. However, the gene from the carrier can be passed to the next generation. Every normal human being has a unit in the body that has the responsibility to repair the damaged DNA. DNA is very significant to life because it is a chain of genetic information in each living cell. Its stability and integrity are very important. Not a lot of people know this, but the rate of damaged DNA is about 1,000 to 1,000,000 molecular lesions per cell per day. It may sounds a lot, but it is only about 0.000165% of the human genome. Damages to the DNA can be caused by two main factors, one if due to the environmental factor, and the other is due to the normal metabolic processes inside the cell. When DNA is being repair properly, everything runs smoothly inside our body. However, when the DNA is damaged and is unrepaired, there could be many problems
Unfixed dna will lead to mutation and diseases. For example, if there are damages to critical genes, such as the tumor suppressor genes, this can cause the gene to malfunction, and may increase the chance of tumor formation. There are many ways which DNa can be repaired, such as nucleotide excision repair (ner) photoreactivation or base excision repair (ber). When an area of dna is damaged, NEr recognizes and locates the damage site. The next step is ner unwinds the lesion, forming a bubble around the damaged dnA. ner will then opens the dna with verification of lesion, incisive of dna by 3 and then by 5 removing the lesion at the same time. Once the previous step is done, ner fills the gap with new dna synthesis and dna ligase joins the gap to gether. With those steps, new dna are generated from time to time. In Xeroderma pigmentosa, individuals are not able to repair damaged DNA caused by ultraviolet light(UV), so therefore the unrepaired dNA can easily e mutated which later on complicates things up. These skin abnormalities are the result of defects in the nucleotide excision repair (ner). The nucleotide excision repair is a dna repair mechanism that specifically protects against mutations. NER is particularly important because this DNA repair mechanism prevent undesired mutations by removing damaged dna caused by Uv light. Everyday, people go out, to school, to work, grocery shopping and so on, and everyday the Uv light is damaging parts DNA, so it would be a tough challenge to stay unexposed to the Uv light. Luckily, the nucleotide excision repair does the job and complete repair the uv-damaged DNA On the other hand, patients with Xeroderma Pigmentosum are notable to do this. When more and more parts of dNa are being damaged by the UV light and left unrepaired One of the most common complications in any XP patients is the development of cancer cells. People who suffer from Xeroderma Pigmentosum have a nearly 100% risk of developing skin cancers. Eye cancers and cancer in other parts of the body can also be developed, but not as common as skin cancers. XP patients who are under 20 years old have a greater chance of getting skin cancer. How great? Compare to a healthy teenage kid, teenage XP patient have 1,000 more chances of developing skin cancer. According to a medical article the median age onset of nonmelanoma skin cancer at 8 year old. Although Xeroderma Pigmentosum is a very serious genetic incurable disease, there are many management methods to help those patients suffer less One of the most common and simple methods is to reduce exposure to the sun This can be done by wearing sunglasses, long sleeves, long pants, optical filtration. However, this method is only effective with patients who are considered in mild cases. There is also a medication that XP patients can take to reduce the number of keratins on the skin this slows down the risk to xp patient developing cancer. In very serious cases, XP patients sometimes will have to wear a"UV-Protective Suit. This suit filter 100 percent UV-light. By wearing this suit, XP patients will be able to go outside the house more. Unfortunately, there is no current permanentcure. Patients who tested positive for Xeroderma Pigmentosum should focus more on how to deal other complications that might happen in the future. XP patients should conside going to frequent body check-up, especially to dermatologist, to check for skin cancer, and also ophthalmologist for eye complications
Unfixed DNA will lead to mutation and diseases. For example, if there are damages to critical genes, such as the tumor suppressor genes, this can cause the gene to malfunction, and may increase the chance of tumor formation. There ar e many ways which DNA can be repaired, such as nucleotide excision repair (NER), photoreactivation or base excision repair (BER). When an area of DNA is damaged, NER recognizes and locates the damage site. The next step is NER unwinds the lesion, forming a bubble around the damaged DNA. NER will then opens the DNA with verification of lesion, incisive of DNA by 3’ and then by 5’ removing the lesion at the same time. Once the previous step is done, NER fills the gap with new DNA synthesis and DNA ligase joins the gap together. With those steps, new DNA are generated from time to time. In Xeroderma pigmentosa, individuals are not able to repair damaged DNA caused by ultraviolet light (UV), so therefore the unrepaired DNA can easily be mutated, which later on complicates things up. These skin abnormalities are the result of defects in the nucleotide excision repair (NER). The nucleotide excision repair is a DNA repair mechanism that specifically protects against mutations. NER is particularly important because this DNA repair mechanism prevent undesired mutations by removing damaged DNA caused by UV light. Everyday, people go out, to school, to work, grocery shopping and so on, and everyday the UV light is damaging parts DNA, so it would be a tough challenge to stay unexposed to the UV light. Luckily, the nucleotide excision repair does the job and complete repair the UV-damaged DNA. On the other hand, patients with Xeroderma Pigmentosum are not able to do this. When more and more parts of DNA are being damaged by the UV light and left unrepaired, mutation occurs. One of the most common complications in any XP patients is the development of cancer cells. People who suffer from Xeroderma Pigmentosum have a nearly 100% risk of developing skin cancers. Eye cancers and cancer in other parts of the body can also be developed, but not as common as skin cancers. XP patients who are under 20 years old have a greater chance of getting skin cancer. How great? Compare to a healthy teenage kid, teenage XP patient have 1,000 more chances of developing skin cancer. According to a medical article, the median age onset of nonmelanoma skin cancer at 8 year old. Although Xeroderma Pigmentosum is a very serious genetic incurable disease, there are many management methods to help those patients suffer less. One of the most common and simple methods is to reduce exposure to the sun. This can be done by wearing sunglasses, long sleeves, long pants, optical filtration. However, this method is only effective with patients who are considered in mild cases. There is also a medication that XP patients can take to reduce the number of keratins on the skin, this slows down the risk to XP patient developing cancer. In very serious cases, XP patients sometimes will have to wear a “ UV-Protective Suit”. This suit filter 100 percent UV-light. By wearing this suit, XP patients will be able to go outside the house more. Unfortunately, there is no current permanent cure. Patients who tested positive for Xeroderma Pigmentosum should focus more on how to deal with other complications that might happen in the future. XP patients should consider going to frequent body check-up, especially to dermatologist, to check for skin cancer, and also ophthalmologist for eye complications
Reference Nucleotide excision Repair and Cancer, 2000 http:/aip.amipatholorg/cgilcontent/full/157/3/693 Xeroderma Pigmentosum http://en.wikipedia.org/wiki/xerodermapigmentosum Xeroderma Pigmentosum, 2005 http://www.thedoctorsdoctor.com/diseases/xerodermapigmentosum.htm
Reference Nucleotide Excision Repair and Cancer, 2000 http://ajp.amjpathol.org/cgi/content/full/157/3/693 Xeroderma Pigmentosum http://en.wikipedia.org/wiki/Xeroderma_pigmentosum Xeroderma Pigmentosum, 2005 http://www.thedoctorsdoctor.com/diseases/xerodermapigmentosum.htm
