Xeroderma Pigmentosum XP

1
Xeroderma Pigmentosum(XP)

• Dana Nasser
• BIO316
• July 29, 2004

2
Outline

• Background
• Causes of XP
• Risks / Symptoms
• Prognosis
• Treatment

3
Background

• First described in 1874 by Hebra and Kaposi. In
  1882
• XP is a rare disorder transmitted in an
  autosomal recessive manner.
• It is characterized by photosensitivity,
  pigmentary changes, premature skin aging, and
  malignant tumor development.
• These manifestations are due to a cellular
  hypersensitivity to ultraviolet (UV) radiation
  resulting from a defect in DNA repair.

4
Statistics

• In the US 1 case per 250,000 population.
• Internationally 1 case per 250,000 population.
  In Japan, it is higher, 1 case per 40,000
  population.
• Mortality/Morbidity .
• The mean patient age of skin cancer is 8 years in
  patients with XP compared to 60 years in the
  healthy population. Actinic damage occurs between
  1 and 2 years of age.
• Race Cases of XP are reported in all races.
• Sex An equal incidence has been reported in
  males and females.
• Age The disease is usually detected at age 1 or
  2 years.

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Causes of XP

• XP is the inheritance of two recessive genes
  (one from each parent). If the parents are only
  carriers of the XP trait (each have one gene and
  one normal gene), they will not show signs or
  symptoms of the disease. By having the two XP
  genes this causes the individual to have an
  extreme sensitivity to UV light and as a result
  experience a range of signs and symptoms of XP.

6
Risks

• Couples who are each carriers of the XP trait are
  at greater risk of producing a child with XP.
• Parents already with a child with XP have a 1 in
  4 chance of having another child with XP.
• XP occurs worldwide and affects people of all
  races. Males and females alike can have the
  condition.

7
Symptoms

• Areas exposed to the sun such as the face show a
  reddening of the skin with scaling and freckling.
  Irregular dark spots may also begin to appear.
• These skin changes progress the neck and lower
  legs. In severe cases the trunk may be involved.
• Over the winter months these changes may
  diminish.

8
Prognosis

• Prognosis Many patients with XP die at an early
  age from skin cancers. However, if a person is
  diagnosed early, does not have severe
  neurological symptoms or has a mild variant, and
  takes all the precautionary measures to avoid
  exposure to UV light, they may survive beyond
  middle age.

9
Treatment

• There is no cure for XP. The main goal of
  treatment is to protect oneself from UV exposure
  and thus prevent the damaging effects it can have
  on the skin.
• Frequent eye examinations by an ophthalmologist.
• Yearly testing (through to age 20) for potential
  neurological problems.

10
References

• http//dermnetnz.org/systemic/xeroderma-pigmentosu
  m.html
• http//www.emedicine.com/derm/topic462.htm