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$Unique_ID{BRK04342}
$Pretitle{}
$Title{Xeroderma Pigmentosum}
$Subject{Xeroderma Pigmentosum Atrophoderma Pigmentosum Kaposi Disease
Melanosis Lenticularis Progressiva XP }
$Volume{}
$Log{}
Copyright (C) 1987, 1988, 1989 National Organization for Rare Disorders, Inc.
339:
Xeroderma Pigmentosum
** IMPORTANT **
It is possible the main title of the article (Xeroderma Pigmentosum) is
not the name you expected. Please check the SYNONYMS listing to find the
alternate names and disorder subdivisions covered by this article.
Synonyms
Atrophoderma Pigmentosum
Kaposi Disease
Melanosis Lenticularis Progressiva
XP
General Discussion
** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only. It should not be used for diagnostic or treatment
purposes. If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.
Xeroderma Pigmentosum is a rare autosomal recessive hereditary disorder
of the skin which begins during early childhood. It is characterized by a
defect in the ability of certain connective tissue cells (fibroblasts) to
repair skin damaged by ultraviolet rays. The skin of people with Xeroderma
Pigmentosum is markedly hypersensitive to sunlight.
Symptoms
The first sign of Xeroderma Pigmentosum is usually freckling on parts of the
skin that have been exposed to sunlight. Linear or star-shaped vascular
lesions (telangiectasias) may appear next. Tumors made up of small blood
vessels (capillary angiomas) may occur on ear margins, the tip of the nose,
and on areas where mucous tissue joins skin such as the mouth. Weakened,
degenerated (atrophic) areas of the skin appear smooth, dry, and light brown.
Malignancies of the skin in people with this disorder may occur before
age 5 through early adulthood. The face and skin of these children may
resemble those of much older individuals. Growth retardation, dwarfism and
mental retardation are also possible.
Ocular symptoms may include abnormal intolerance to light (photophobia),
excessive tears in the eyes (lacrimation), inflammation of the cornea
(keratitis), clouding of the lens of the eye (opacities), and tumors of the
eyelid or the cornea.
Causes
Xeroderma Pigmentosum (XP) is an autosomal recessive hereditary disorder. A
deficit in the ability to repair the building blocks of genes (DNA), and the
inability of certain types of connective tissue cells (fibroblasts) to repair
damaged skin, cause the symptoms of this disorder.
Human traits including the classic genetic diseases, are the product of
the interaction of two genes for that condition, one received from the father
and one from the mother. In recessive disorders, the condition does not
appear unless a person inherits the same defective gene from each parent. If
one receives one normal gene and one gene for the disease, the person will be
a carrier for the disease, but usually will show no symptoms. The risk of
transmitting the disease to the children of a couple, both of whom are
carriers for a recessive disorder, is twenty-five percent. Fifty percent of
their children will be carriers, but healthy as described above. Twenty-five
percent of their children will receive both normal genes, one from each
parent and will be genetically normal.
People with XP are markedly hypersensitive to the ultraviolet rays of
sunlight which causes damage to DNA. Exposure to cancer causing agents
(carcinogens) in the environment may also damage DNA. Indirectly, these
agents may exacerbate XP in people who are genetically susceptible.
Affected Population
Xeroderma Pigmentosum may affect children of both sexes as early as the first
year of life. Skin malignancies may appear before age 5. The disorder is
more common in Japan and Egypt than in Europe and America. The disorder
affects approximately 250,000 in the United States. Xeroderma Pigmentosum
affects approximately one in one million people.
Related Disorders
There are many types of skin cancers, some of which are quite common.
Malignant Melanoma of the skin is a malignant tumor of melanocyte origin.
These tumors may appear in different sizes, shapes, and shades of color
(mostly pigmented). The tumors have a variable ability for spreading to
adjacent parts of the body, or through the blood and lymph circulation to
other organs.
Basal Cell Carcinomas (Rodent Ulcer) may appear as small, shiny, firm
nodules; ulcerated, crusted lesions; flat, scar-like hardened plaques; or
lesions difficult to differentiate from psoriasis or localized dermatitis.
Squamous Cell Carcinomas are a common form of skin cancer that usually
appears on sun-exposed areas of the skin, but may occur anywhere on the body.
The lesions begin as a small red elevation or plaque with a scaly or crusted
surface. They may then become nodular, sometimes with a warty surface.
Therapies: Standard
Total protection of the skin from sunlight in children with Xeroderma
Pigmentosum can prevent additional lesions of the skin.
Surgery, either extensive or limited, may be performed with limited
success.
Other treatment of Xeroderma Pigmentosum is symptomatic and supportive.
Therapies: Investigational
Application of an experimental cream containing catalase appears to hold
promise for prevention of tumors in some children with Xeroderma Pigmentosum.
Ointments containing vitamin A derivatives are also being investigated.
Isotretinoin (Accutane) has been known to reduce the recurrence of tumors in
people with Xeroderma Pigmentosum. However, the drug is very toxic and many
people cannot tolerate side effects.
T4 Endonuclease V.B. Liposome Encapsulated (T4N5) is a new orphan drug being
used in the prevention of skin cancers and other skin abnormalities associated
with patients diagnosed with xerodermas pigmentosum (XP). It is manufactured
by Applied Genetics, Inc. 205 Buffalo Ave., Freeport, NY 11520.
This disease entry is based upon medical information available through
October 1989. Since NORD's resources are limited, it is not possible to keep
every entry in the Rare Disease Database completely current and accurate.
Please check with the agencies listed in the Resources section for the most
current information about this disorder.
Resources
For more information on Xeroderma Pigmentosum, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
Xeroderma Pigmentosum Registry
c/o Department of Pathology
Room 520, Medical Science Bldg.
UMDNJ - New Jersey Medical School
100 Bergen Street
Newark, NJ 07103
(201) 456-6255
The National Arthritis and Musculoskeletal and Skin Diseases Information
Clearinghouse
Box AMS
Bethesda, MD 20892
(301) 495-4484
The Skin Cancer Foundation
475 Park Avenue South
New York, NY 10016
(212) 725-5176
NIH/National Cancer Institute
9000 Rockville Pike, Bldg. 31, Rm. 1A2A
Bethesda, MD 20892
1-800-4-CANCER
The National Cancer Institute has developed PDQ (Physician Data Query), a
computerized database designed to give doctors quick and easy access to many
types of information vital to treating patients with this and many other
types of cancer. To gain access to this service, a doctor can contact the
Cancer Information Service offices at 1-800-4-CANCER. Information
specialists at this toll-free number can answer questions about cancer
prevention, diagnosis, and treatment.
For genetic information and genetic counseling referrals, please contact:
March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
(914) 428-7100
Alliance of Genetic Support Groups
35 Wisconsin Circle, Suite 440
Chevy Chase, MD 20815
(800) 336-GENE
(301) 652-5553
References
XERODERMA PIGMENTOSUM, DEFECTIVE DNA REPAIR--AND SCHISTOSOMIASIS?: J.
German; Annales de Genetique - Paris (1980: issue 23,2). Pp. 69-72.
MICROINJECTION OF HUMAN CELL EXTRACTS CORRECTS XERODERMA PIGMENTOSUM DEFECT:
A. J. de Jonge, et al.; EMBO Journal (1983: issue 2,5). Pp. 637-641.