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Xeroderma pigmentosum, or XP, is an autosomal recessive genetic disorder of DNA repair in which the body's normal ability to remove damage caused by ultraviolet (UV) light is deficient. This leads to multiple basaliomas and other skin malignancies at a young age. In severe cases, it is necessary to avoid sunlight completely. Image File history File links Question_book-3. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // Q00-Q99 - Congenital malformations, deformations and chromosomal abnormalities (Q00-Q07) Congenital malformations of the nervous system (Q00) Anencephaly and similar malformations (Q01) Encephalocele (Q02) Microcephaly (Q03) Congenital hydrocephalus (Q04) Other congenital malformations of brain (Q05) Spina bifida (Q06) Other congenital malformations of spinal cord (Q07) Other congenital malformations of nervous... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... A genetic disorder is a disease caused by abnormalities in genes or chromosomes. ... DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... For other uses, see Ultraviolet (disambiguation). ... Basal cell carcinoma (BCC) is the most common skin cancer in humans. ... When normal cells are damaged or old they undergo apoptosis; cancer cells, however, avoid apoptosis. ...

Causes

Damage to DNA in epidermal cells occurs during exposure to UV light. The absorption of the high energy light leads to the formation of pyrimidine dimers, namely CPDs (Cyclobutane-Pyrimidine-Dimers) and 6-4PP (pyrimidine-6-4-pyrimidone photoproducts). The normal repair process is called nucleotide excision repair. The damage is excised by endonucleases, then the gap is filled by a DNA polymerase and sealed by a ligase. The most common defect in xeroderma pigmentosum is a genetic defect whereby nucleotide excision repair (NER) enzymes are mutated, leading to a reduction in or elimination of NER. The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Look up Epidermis in Wiktionary, the free dictionary. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring [1]. It is isomeric with two other forms of diazine. ... Sucrose, or common table sugar, is composed of glucose and fructose. ... Cyclobutane, C4H8, with a molecular mass of 56. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring [1]. It is isomeric with two other forms of diazine. ... Sucrose, or common table sugar, is composed of glucose and fructose. ... // Nucleotide Excision Repair DNA constantly requires repair due to chemical damage that can occur to bases, and nucleotide excision repair (NER) is one of the mechanisms by which the cell can prevent unwanted mutations caused by base damage (see also Base excision repair). ... Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. ... 3D structure of the DNA-binding helix-hairpin-helix motifs in human DNA polymerase beta A DNA polymerase is an enzyme that assists in DNA replication. ... It has been suggested that sticky end/blunt end be merged into this article or section. ... // Nucleotide Excision Repair DNA constantly requires repair due to chemical damage that can occur to bases, and nucleotide excision repair (NER) is one of the mechanisms by which the cell can prevent unwanted mutations caused by base damage (see also Base excision repair). ...

Unrepaired damage can lead to mutations, altering the information of the DNA. If mutations affect important genes, like tumour suppressor genes (e.g. p53) or proto oncogenes then this may lead to cancer. Since in XP patients the frequencies of mutations is much elevated, these patients have a predisposition for cancer. TP53 bound to a short DNA fragment. ... An oncogene is a modified gene, or a set of nucleotides that codes for a protein, that increases the malignancy of a tumor cell. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ...

Types

There are 7 complementation groups, plus one variant form:

The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... Short and long arms Chromosome. ... 3D structure of the DNA-binding helix-hairpin-helix motifs in human DNA polymerase beta A DNA polymerase is an enzyme that assists in DNA replication. ... DNA replication. ...

Symptoms

Some of the most common symptoms of XP are: The term symptom (from the Greek meaning chance, mishap or casualty, itself derived from συμπιπτω meaning to fall upon or to happen to) has two similar meanings in the context of physical and mental health: Strictly, a symptom is a sensation or change in health function experienced by a patient. ...

• An unusually severe sunburn after a short sun exposure. The sunburn may last for several weeks. The sunburn usually occurs during a child’s first sun exposure.
• Development of many freckles at an early age.
• Irregular dark spots on the skin.
• Thin skin.
• Excessive dryness of skin.
• Rough-surfaced growths (solar keratoses), and skin cancers.
• Eyes that are painfully sensitive to the sun and may easily become irritated, bloodshot, and clouded.
• Blistering or freckling on minimum sun exposure.
• Premature aging of skin, lips, eyes, mouth and tongue.

Freckles are small colored spots of melanin on the exposed skin or membrane of people with complexions fair enough for them to be visible. ... For the packaging type, see Blister pack. ...

Treatment

The most important part of managing the condition is reducing exposure to the sun. One way of acheiving this is moving to Las Vegas where they have public night schools and people can live a normal life with no sun exposure.

The number of keratoses can be reduced with Isotretinoin ([1]) (though there are significant side-effects.) Existing keratoses can be treated using cryotherapy or fluorouracil.^[1] Keratosis can refer to: actinic keratosis (also known as solar keratosis) seborrheic keratosis keratosis pilaris (KP) Category: ... Isotretinoin (INN) (IPA: ) is a medication used for the treatment of severe acne. ... An adverse drug reaction (abbreviated ADR) is a term to describe the unwanted, negative consequences sometimes associated with the use of medications. ... Keratosis can refer to: actinic keratosis (also known as solar keratosis) seborrheic keratosis keratosis pilaris (KP) Category: ... Cryotherapy is used to define several techniques and procedures in the medical community. ... Fluorouracil (5-FU) is a drug that is used in the treatment of cancer. ...

In popular culture

• A notable fictional character who suffers from XP is Christopher Snow featured in the novels Fear Nothing and Seize the Night by Dean Koontz.
• The Lifetime Network movie Children of the Dark (1994) is about two young girls who have been diagnosed with an extreme case of XP and how their family copes with it.
• Lurlene McDaniel's "Night Vision" tells the story of a lonely girl with extreme XP and a young man who befriends her.
• The television miniseries Ultraviolet includes a character, Oliver, who has XP.
• In the television series Forever Knight, the main character is a vampire who explains his aversion to sunlight by claiming he has XP.
• In the 2001 film The Others, the two main child characters have XP.
• During the second season of ABC's Extreme Makeover: Home Edition, the Pope family was selected for an Extreme Makeover as their daughter, Shelby, suffers from XP. Later, ABC and the Popes teamed with Walt Disney World to give XP children a special treat – Walt Disney World made a special night-time opening (midnight to 4 AM) so XP children could spend time at the popular park. Footage from this event aired as part of an Extreme Makeover holiday special on December 11, 2005.
• The 2006 Japanese movie and TV series Taiyou no uta is about an 16-year-old girl named Kaoru, who has XP. Kaoru has a talent for singing and songwriting with a guitar, but XP starts to ravage her guitar playing, by which her friend Koji began to accompany her on guitar instead, and soon, other friends joined in to form a band they called Moon Child.
• The Girl who Lives in the Dark (2006) documents the story of Wan Lao Yang. Wan Lao Yang is a 9-year-old girl from China suffering from XP. This film documents Wan Lao’s journey to Shanghai, and the treatment she receives from a specialist from the famous Great Ormornd Street Hospital. It also explores the work of NASA’s Sun Protection Team which has created a customised ‘sun suit’ for Wan Lao that blocks out 100% of U.V. light.
• In the anime Ouran High School Host Club, the occult-obsessed character Umehito Nekozawa seems to suffer from XP, but whether it is clinical or that he simply does not like the light remains unknown.
• In the video game Ace Combat 3, Rena Hirose suffers from the fictional "Silver Stone Disease", which has similar (if not the same) symptoms as XP.
• In the novel "A Cool Moonlight" by Angela Johnson, the main character Lila suffers from XP.

The Moonlight Bay Trilogy will be a trilogy of three novels by Dean Koontz. ... The Moonlight Bay Trilogy will be a trilogy of three novels by Dean Koontz. ... Dean Ray Koontz (born July 9, 1945 in Everett, Pennsylvania), also known under a number of pseudonyms, including Leigh Nichols, is an American writer. ... This article needs additional references or sources for verification. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... Plural of Girl. ... Lurlene McDaniel (born c. ... For other uses, see Ultraviolet (disambiguation). ... Forever Knight is a Canadian-German-American television series about Nick Knight, an 800-year-old vampire working as a detective in modern day Toronto. ... The Others is a 2001 psychological thriller film by the Spanish director Alejandro Amenábar, starring Nicole Kidman. ... Extreme Makeover: Home Edition is an ABC reality television series that began broadcasting in 2003 in which a familys house, including all rooms, exterior and landscaping, is made over by a team of builders and designers in seven days. ... Cinderella Castle, at the center of the Magic Kingdom, is Walt Disney World Resorts most recognizable icon Introduction Owned and operated by The Walt Disney Company, the Walt Disney World Resort in Florida, USA is home to four theme parks, two water parks, several resort hotels and golf courses... December 11 is the 345th day of the year (346th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Midnight Sun , lit. ... Serialized in LaLa Original run August 5, 2003 – Ongoing No. ... Ace Combat 3: Electrosphere is the third installment in the Ace Combat series of games. ...

See also

• Biogerontology
• Cockayne syndrome
• Photophobia
• Senescence
• XPB

Gerontology is the study of the elderly, and of the aging process itself. ... Cockayne syndrome is a rare disorder characterized by growth failure, impaired development of the nervous system, abnormal sensitivity to sunlight (photosensitivity), and premature aging. ... Photophobia (also light sensitivity) or fear of light, is a symptom of excessive sensitivity to light and the aversion to sunlight or well-lit places. ... In biology, senescence is the combination of processes of deterioration which follow the period of development of an organism. ... XPB (Xeroderma Pigmentosum B) is an ATP dependent human DNA helicase that is a part of the TFIIH transcription factor complex. ...

References

1. ^ DermNet systemic/xeroderma-pigmentosum

The New Zealand Dermatological Society is a medical organization best known outside New Zealand for its DermNet website, which provides photographs and descriptions of many skin conditions. ...

External links

• XP Society
• XP Family Support Group
• UK Patient Support Group
• An article about this disorder in English and Italian
• Web Site of a Short Film about an Xeroderma pigmentosum (XP) Patient. Film is directed by Kimberly Williams Paisley
• Article About the Xeroderma pigmentosum (XP) Society by William Lambers (pdf format)