Xeroderma Pigmentosum, Variant Type (XPV)

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MedlinePlus Genetics: ⁴² Xeroderma pigmentosum, which is commonly known as XP, is an inherited condition characterized by an extreme sensitivity to ultraviolet (UV) rays from sunlight. This condition mostly affects the eyes and areas of skin exposed to the sun. Some affected individuals also have problems involving the nervous system.The signs of xeroderma pigmentosum usually appear in infancy or early childhood. Many affected children develop a severe sunburn after spending just a few minutes in the sun. The sunburn causes redness and blistering that can last for weeks. Other affected children do not get sunburned with minimal sun exposure, but instead tan normally. By age 2, almost all children with xeroderma pigmentosum develop freckling of the skin in sun-exposed areas (such as the face, arms, and lips); this type of freckling rarely occurs in young children without the disorder. In affected individuals, exposure to sunlight often causes dry skin (xeroderma) and changes in skin coloring (pigmentation). This combination of features gives the condition its name, xeroderma pigmentosum.People with xeroderma pigmentosum have a greatly increased risk of developing skin cancer. Without sun protection, about half of children with this condition develop their first skin cancer by age 10. Most people with xeroderma pigmentosum develop multiple skin cancers during their lifetime. These cancers occur most often on the face, lips, and eyelids. Cancer can also develop on the scalp, in the eyes, and on the tip of the tongue. Studies suggest that people with xeroderma pigmentosum may also have an increased risk of other types of cancer, including brain tumors. Additionally, affected individuals who smoke cigarettes have a significantly increased risk of lung cancer.The eyes of people with xeroderma pigmentosum may be painfully sensitive to UV rays from the sun. If the eyes are not protected from the sun, they may become bloodshot and irritated, and the clear front covering of the eyes (the cornea) may become cloudy. In some people, the eyelashes fall out and the eyelids may be thin and turn abnormally inward or outward. In addition to an increased risk of eye cancer, xeroderma pigmentosum is associated with noncancerous growths on the eye. Many of these eye abnormalities can impair vision.About 30 percent of people with xeroderma pigmentosum develop progressive neurological abnormalities in addition to problems involving the skin and eyes. These abnormalities can include hearing loss, poor coordination, difficulty walking, movement problems, loss of intellectual function, difficulty swallowing and talking, and seizures. When these neurological problems occur, they tend to worsen with time.Researchers have identified at least eight inherited forms of xeroderma pigmentosum: complementation group A (XP-A) through complementation group G (XP-G) plus a variant type (XP-V). The types are distinguished by their genetic cause. All of the types increase skin cancer risk, although some are more likely than others to be associated with neurological abnormalities.

MalaCards based summary: Xeroderma Pigmentosum, Variant Type, also known as xeroderma pigmentosum, is related to xeroderma pigmentosum, complementation group f and de sanctis-cacchione syndrome. An important gene associated with Xeroderma Pigmentosum, Variant Type is POLH (DNA Polymerase Eta), and among its related pathways/superpathways are Homology Directed Repair and Transcription-Coupled Nucleotide Excision Repair (TC-NER). The drugs Afamelanotide and Lenalidomide have been mentioned in the context of this disorder. Affiliated tissues include skin, eye and tongue, and related phenotypes are failure to thrive and eeg abnormality

GARD: ¹⁹ Xeroderma pigmentosum (XP) causes the skin and eyes to be extra sensitive to exposure to ultraviolet radiation from the sun and other sources. Symptoms begin in early childhood. People with XP can develop bad sunburns, blistering, and freckling in response to sunlight. The eyes may develop light sensitivity, corneal clouding, and swelling. Some people with XP have nervous system involvement as well. People with XP are at very high risk of developing skin cancer and other types of cancers. XP is caused by variants in one of at least nine genes involved in repairing damaged DNA. XP is inherited in an autosomal recessive pattern. Diagnosis is based on the clinical findings and specialized testing on skin cells. The diagnosis can be confirmed by the results of genetic testing.

OMIM®: ⁵⁷ Xeroderma pigmentosum is an autosomal recessive disorder characterized by increased sensitivity to sunlight and defects in DNA repair. For a general overview of the disorder, see XPA (278700). Some patients with xeroderma pigmentosum have been found to have normal DNA excision repair, but defective postreplication repair (Lehman et al., 1975). This XP 'variant' class is characterized by a defect in conversion of newly synthesized DNA from low to high molecular weight after UV irradiation (Masutani et al., 1999). So-called 'pigmentary xerodermoid' is apparently identical to the XP variant, which is characterized by loss of a gene product that permits normal cells to replicate DNA without interruption at UV-damaged sites (Cleaver et al., 1980). (278750) (Updated 08-Dec-2022)

UniProtKB/Swiss-Prot: ⁷³ An autosomal recessive pigmentary skin disorder characterized by solar hypersensitivity of the skin, high predisposition for developing cancers on areas exposed to sunlight and, in some cases, neurological abnormalities. XPV shows normal nucleotide excision repair, but an exaggerated delay in recovery of replicative DNA synthesis. Most patients with the variant type of xeroderma pigmentosum do not develop clinical symptoms and skin neoplasias until a later age. Clinical manifestations are limited to photo-induced deterioration of the skin and eyes.

Orphanet ⁵⁸ Xeroderma pigmentosum variant: Xeroderma pigmentosum variant is a milder subtype of xeroderma pigmentosum (XP; see this term), a rare genetic photodermatosis characterized by severe sun sensitivity and an increased risk of skin cancer.

Xeroderma pigmentosum: Xeroderma pigmentosum (XP) is a rare genodermatosis characterized by extreme sensitivity to ultraviolet (UV)-induced changes in the skin and eyes, and multiple skin cancers. It is subdivided into 8 complementation groups, according to the affected gene: classical XP (XPA to XPG) and XP variant (XPV) (see these terms).

Disease Ontology ¹¹ Xeroderma pigmentosum: A syndrome that is characterized by a deficiency in the ability to repair ultraviolet damage that has material basis in autosomal recessive inheritance of DNA repair.

Xeroderma pigmentosum variant type: A xeroderma pigmentosum characterized by normal DNA excision repair, but defective postreplication repair that has material basis in mutations in the POLH gene on chromosome 6p21.1.

Wikipedia ⁷⁵ Desanctis-cacchione syndrome: DeSanctis-Cacchione syndrome or Xeroderma pigmentosum is a genetic disorder characterized by the skin... more...

Xeroderma pigmentosum: Xeroderma pigmentosum (XP) is a genetic disorder in which there is a decreased ability to repair DNA... more...

Clinical features from OMIM®:

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