xeroderma pigmentosum group A

What is Xeroderma Pigmentosum Group A?

Xeroderma pigmentosum (XP) is an inherited condition characterized by an extreme sensitivity to ultraviolet (UV) rays from sunlight. Thus, the areas of the body that are most affected by the condition are the skin and eyes. XP’s name comes from two of its common characteristics: dry skin (xeroderma) and skin color changes (pigmentosum). There are multiple types of XP, some with different features that are captured by the groupings, but all types include sensitivity to UV light.

The onset of symptoms for individuals with XP group A (XPA) is usually in infancy, but some individuals may have later onset. Typically, XPA is diagnosed in infants who have been sunburned after minimal time in sunlight. Affected children also develop excessive freckling of sun-exposed areas. Damage from the UV rays significantly increases the risk of skin cancer in children with XPA. The average age of onset for non-melanoma skin cancer in children with any type of XP is 9 years and for melanoma is 22 years. The eye is also susceptible to damage from UV light resulting in impaired vision due to clouding of the cornea, inflammation of the cornea, non-cancerous growths on the eye, and/or eye cancer.

Other abnormalities that occur in individuals with XPA, but are unlikely to be related to UV damage, include neurological abnormalities and internal cancers. At least 25 to 30% of individuals with XPA have progressive neurological issues that may include hearing loss, difficulty swallowing and talking, movement problems, seizures, and intellectual disability. The risk for internal cancers is thought to be linked to environmental carcinogens, like cigarette smoke and other, potentially uncontrollable, exposures.

How common is Xeroderma Pigmentosum Group A?

Worldwide, XP has been estimated to affect about 1 in 100,000 individuals. In Japan, the incidence of XPA is approximately 1 in 40,000 individuals. Countries in North Africa, the Middle East, and South Asia may also have a higher frequency of XPA patients.

How is Xeroderma Pigmentosum Group A treated?

Management for all types of XP involves strictly avoiding sun and UV light, especially on the skin and eyes. Skin-covering clothing, sunscreen, and sunglasses with UV protection are strongly recommended. Avoidance of carcinogens, like cigarette smoke, is also recommended. Treatment of individuals with XP is typically multidisciplinary. Individuals are regularly seen by dermatologists to remove skin growths and may be prescribed high doses of a special form of vitamin D to prevent additional growths although there are many side effects. Ophthalmologists are also involved in patient care to regularly examine the eyes for damage. A neurologist and audiologist may aid in monitoring, diagnosis, and management of neurological features. Oncologists will become involved if an internal cancer is diagnosed.

What is the prognosis for a person with Xeroderma Pigmentosum Group A?

The prognosis for an individual with XPA is generally poor due to the early onset of symptoms and severity of features. The life expectancy is shortened for many individuals with XPA due to the dramatically increased risk of skin cancer and risk for neurodegeneration. The average life expectancy of an individual with any type of XP with neurological features is 29 years (37 years if neurological features are not present).