XERODERMA PIGMENTOSUM

Xeroderma Pigmentosum, or XP for short, is a hereditary disorder characterized by a high sensitivity to ultraviolet (UV) rays from the sun. This illness primarily affects the eyes and sun-exposed parts of the skin. Some people who are impacted also have problems with their nervous systems.

Xeroderma pigmentosum symptoms typically occur in infancy or early childhood. After only a few minutes in the sun, many of the youngsters who are impacted suffer a severe sunburn. Redness and blistering from a sunburn can continue for weeks. Other affected children do not get sunburned even when exposed to the sun for short periods of time, but instead tan normally. Almost all children with Xeroderma Pigmentosum acquire freckling of the skin in sun-exposed areas (such as the face, arms, and lips) by the age of two; this form of freckling happens only rarely in young children who do not have the disorder. Sunlight exposure produces dry skin (Xeroderma) and skin color changes in those who are affected (Pigmentation).

People who have xeroderma pigmentosum have a much higher chance of getting skin cancer. Half of children with this syndrome have their first skin cancer by the age of ten if they are not protected from the sun. The majority of patients who have xeroderma pigmentosum acquire several skin malignancies over the course of their lives. The face, lips, and eyelids are the most common sites for these malignancies. On the scalp, in the eyes, and on the tip of the tongue, cancer can grow. According to studies, patients with xeroderma pigmentosum are more likely to develop other cancers, such as brain tumors. Furthermore, smokers who are impacted have a greatly higher risk of lung cancer.

In addition to skin and visual difficulties, over 30% of persons with Xeroderma Pigmentosum experience increasing neurological disorders. Hearing loss, poor coordination, difficulties walking, mobility problems, loss of intellectual function, difficulty swallowing and communicating, and convulsions are examples of these disorders. When neurological issues arise, they tend to get worse over time. At least eight hereditary types of Xeroderma Pigmentosum have been found, ranging from complementation group A (XP-A) through complementation group G (XP-G), including a variant variety (XP-V).

 The types are distinguished by the genetic cause of their existence. Although all of the types increase the risk of skin cancer, some are more likely than others to be linked to neurological abnormalities.

(Xeroderma Pigmentosum, 2020)

What causes Xeroderma Pigmentosum (pigmentation of the skin)?

Xeroderma Pigmentosum is an autosomal recessive hereditary condition, which implies that each parent has a defective Xeroderma Pigmentosum gene. Carriers of the Xeroderma Pigmentosum trait have one Xeroderma Pigmentosum gene and one normal gene, but they have no symptoms or signs of the condition.

A defective nucleotide excision repair (NER) mechanism causes the signs and symptoms of Xeroderma Pigmentosum. There are two different forms of NER:

l  Transcription-coupled (TC)-NER

l  Genome (GG)-NER.

 

In diverse families (XPA to XPG), at least seven separate gene anomalies or complementation groups have been described, resulting in varied disease severity.

l  XPA and XPC are two often used acronyms.

l  XPE is a rather uncommon substance.

l  XPG is a serious condition.

l  XPF is a gentle compound.

In addition to the hereditary defect, UV exposure has immuno-suppressive effects, which contribute to the condition by diminishing Langerhans cells in the epidermis, for example.

 

What are the symptoms of xeroderma pigmentosum?

Xeroderma Pigmentosum is usually discovered in early childhood, between the ages of 1-2.

A child who develops severe sunburn after their first exposure to the sun could be a sign of Xeroderma Pigmentosum. The DNA repair factor may usually be measured from skin or blood samples to confirm a diagnosis of Xeroderma Pigmentosum.

 

 What are the options for treating xeroderma pigmentosum?

 Xeroderma pigmentosum has no known cure. Gene therapy for xeroderma pigmentosum is currently considered hypothetical and experimental.

Genetic counselling should be sought by family members and known carriers, and consanguineous marriage should be avoided.

Prenatal diagnosis of a fetus at risk of xeroderma pigmentosum can be done via amniocentesis, chorionic villi sampling, and chromosomal breakage investigations.

 The main purpose of therapy is to guard against UV rays from the sun and fluorescent lamps that are not shielded (sun avoidance).

l  Outdoor activities should be limited to the evenings; throughout the day, stay indoors.

l  Put on protective gear (long sleeves and pants, shirts with collars, tightly woven fabrics, wide-brimmed hat).

l  Wraparound sunglasses that block UV rays protect your eyes.

l  All exposed regions should be covered with broad-spectrum sunscreens with an SPF of 50 or higher.

Patients should get their skin examined on a regular basis by someone who has been trained to recognize the signs of skin cancer. Any abnormal patches or growths should be reported to your doctor right once.

 

l  At least every 3 to 6 months, have your skin examined by a doctor (ideally a dermatologist).

l  Cryotherapy or 5-fluorouracil cream can be used to treat actinic keratoses. Biopsies should be performed on any suspected growths. The majority of skin malignancies are surgically removed.

l  An ophthalmologist should examine your eyes on a regular basis.

l  Testing for probable neurological disorders on a yearly basis (up until the age of 20).

Isotretinoin may be administered to some xeroderma pigmentosum patients. By changing keratinocyte development, this vitamin A derivative may inhibit the genesis of new malignancies.

 

What happens if you have Xeroderma Pigmentosum?

 Many people with Xeroderma Pigmentosum die of skin malignancies at a young age. However, if a person is discovered early, does not have serious neurological symptoms or has a minor variety, and takes all precautions to avoid UV rays, they may live well into their middle years.

Xeroderma Pigmentosum patients and their families will confront numerous challenges in their daily lives. The importance of constant education and reminders about the need to shield oneself from the sun is critical in the treatment of Xeroderma Pigmentosum.

(Ngan, 2017)

 

References

Ngan, V. (2017, October). Xeroderma Pigmentosum. Retrieved from DermNet NZ: https://dermnetnz.org/topics/xeroderma-pigmentosum

Xeroderma Pigmentosum. (2020, August 18). Retrieved from Medline Plus: https://medlineplus.gov/genetics/condition/xeroderma-pigmentosum/

 

By: Maha Aslam