What type of mutation causes xeroderma pigmentosum

Frequent skin examination by a family member who is familiar with the features of XP-associated skin cancers. Regular eye examinations by an ophthalmologist, which is a medical doctor who specializes in eye care, and mouth examinations by a dentist.

Due to the high risk of multiple skin cancers, people with XP should avoid being in the sunlight unprotected. They should cover their skin completely and wear UV-absorbing sunglasses when outside. Learn more about protecting your skin from the sun. People with XP are also sensitive to UV type C rays given off by some artificial indoor light sources. Even halogen bulbs and some fluorescent bulbs give off sufficient UV to burn some individuals, so UV protection indoors may also be needed.

Your team may recommend taking a vitamin B3 supplement nicotinamide that has been shown to reduce the appearance of skin cancers in the general population. Screening recommendations may change over time as new technologies are developed and more is learned about XP. It is important to talk with your health care team about appropriate screening tests. Learn more about what to expect when having common tests, procedures, and scans.

If you are concerned about your risk of cancer, talk with your health care team. It can be helpful to bring someone along to your appointments to take notes. Consider asking your health care team the following questions:. If you are concerned about your family history and think you or other family members may have XP, consider asking the following questions:. Should my family and I consider genetic testing? The Genetics of Cancer. Genetic Testing.

Collecting Your Family Cancer History. Xeroderma Pigmentosum Society American Academy of Dermatology National Organization for Rare Disorders To find a genetic counselor in your area, ask your health care team or visit the following website:. National Society of Genetic Counselors. Xeroderma Pigmentosum Approved by the Cancer.

What is xeroderma pigmentosum? What causes XP? How is XP inherited? How common is XP? Home arrow-right-small-blue Topics A—Z arrow-right-small-blue Xeroderma pigmentosum. Author: Vanessa Ngan, Staff Writer, October Xeroderma pigmentosum XP is a very rare skin disorder where a person is highly sensitive to sunlight , has premature skin ageing and is prone to developing skin cancers.

Xeroderma pigmentosum is caused by cellular hypersensitivity to ultraviolet UV radiation, as a result of a defect in the DNA repair system. Xeroderma pigmentosum has also been called DeSanctis-Cacchione syndrome. Xeroderma pigmentosum is an autosomally recessive inherited disease, which means that a faulty xeroderma pigmentosum gene comes from each parent. Carriers of the xeroderma pigmentosum trait have one xeroderma pigmentosum gene and one normal gene and do not show signs or symptoms of the disease.

The signs and symptoms of xeroderma pigmentosum are a result of an impaired nucleotide excision repair NER system. Two types of NER have been identified:.

At least seven different gene abnormalities or complementation groups have been described in different families XPA to XPG resulting in varying disease severity. In addition to the genetic abnormality , the immunosuppressive effects of exposure to ultraviolet radiation UV contribute to the disease, for example by depleting Langerhans cells from the epidermis.

Couples who are each a carrier of the xeroderma pigmentosum trait are at greater risk of producing a child with xeroderma pigmentosum. Parents already with a child with xeroderma pigmentosum have a 1 in 4 chance of having another child with xeroderma pigmentosum. Xeroderma pigmentosum occurs worldwide and affects men and women of all races. Normal cells are usually able to fix DNA damage before it causes problems. However, in people with xeroderma pigmentosum, DNA damage is not repaired normally.

As more abnormalities form in DNA, cells malfunction and eventually become cancerous or die. Many of the genes related to xeroderma pigmentosum are part of a DNA-repair process known as nucleotide excision repair NER. The proteins produced from these genes play a variety of roles in this process. They recognize DNA damage, unwind regions of DNA where the damage has occurred, snip out excise the abnormal sections, and replace the damaged areas with the correct DNA.

Inherited abnormalities in the NER-related genes prevent cells from carrying out one or more of these steps. The major features of xeroderma pigmentosum result from a buildup of unrepaired DNA damage. When UV rays damage genes that control cell growth and division, cells can either die or grow too fast and in an uncontrolled way. Unregulated cell growth can lead to the development of cancerous tumors. Neurological abnormalities are also thought to result from an accumulation of DNA damage, although the brain is not exposed to UV rays.

Researchers suspect that other factors damage DNA in nerve cells. It is unclear why some people with xeroderma pigmentosum develop neurological abnormalities and others do not. Inherited mutations in at least eight genes have been found to cause xeroderma pigmentosum.

Mutations in the other genes generally account for a smaller percentage of cases. This condition is inherited in an autosomal recessive pattern , which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

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Xeroderma pigmentosum. From Genetics Home Reference. Description Xeroderma pigmentosum, which is commonly known as XP, is an inherited condition characterized by an extreme sensitivity to ultraviolet UV rays from sunlight. Frequency Xeroderma pigmentosum is a rare disorder; it is estimated to affect about 1 in 1 million people in the United States and Europe.