Which of the following people are more susceptibe to UV light induced
carcinogenesis?
1. People with xeroderma pigmentosa
2. Fanconis anemia
3. Telangiectasia
4. All of the above
📝 Explanation:
1. People with Xeroderma Pigmentosum (XP):
Xeroderma pigmentosum is a rare genetic disorder that affects the way the skin
and eyes repair damage from UV radiation. Individuals with XP have a deficiency
in the DNA repair mechanism that normally removes UV-induced lesions. As a
result, their cells are more prone to mutations, which can lead to skin cancer.
There are several types of XP, and they vary in severity, but all are
characterized by extreme sensitivity to UV light, leading to early aging of the
skin, pigmentation changes, and a high risk of developing multiple skin cancers,
including melanoma, at a very young age.
2. Fanconi Anemia:
Fanconi anemia is another genetic disorder that affects the body's ability to
repair DNA. It is not exclusively related to UV radiation but rather to a defect
in the repair of DNA crosslinks, which can be caused by various agents,
including UV light. Patients with Fanconi anemia have an increased
susceptibility to various cancers, including skin cancers. Their cells have a
higher frequency of chromosomal instability and DNA damage, which can be
exacerbated by UV exposure. However, it's essential to note that the primary
cancer risk in Fanconi anemia is related to the underlying defect in DNA repair
and not solely to UV light.
3. Telangiectasia:
Telangiectasia is a condition where small blood vessels, especially those in the
skin, widen and become visible. While telangiectasia itself does not increase
the risk of skin cancer, individuals with certain forms of this condition may
have a higher susceptibility to UV light damage. For example, some patients with
telangiectasia may also have a genetic mutation or an acquired defect in the
skin that results in poor repair of UV-induced DNA damage. This can lead to a
higher risk of developing non-melanoma skin cancers like basal cell carcinoma
and squamous cell carcinoma. Moreover, telangiectasias are often found in areas
of the skin that have been exposed to significant UV radiation, such as the
face, neck, and hands, which are common sites for these types of skin cancers.
In summary, all of the conditions mentioned (Xeroderma Pigmentosum, Fanconi
Anemia, and Telangiectasia) can increase the susceptibility to UV light-induced
carcinogenesis due to their respective impairments in DNA repair mechanisms and
skin responses to UV radiation.
MCQ