In humans, xeroderma pigmentosum (XP) is a disorder of the nucleotide excision repair mechanism. These individuals are unable to repair DNA damage caused by ultraviolet light. Which of the following are the most prominent types of DNA lesions in individuals suffering from xeroderma pigmentosum

 Modified Bases, Single-stranded breaks and double-stranded breaks

Explanation:

Modified Bases are the type of lesions which a xeroderma pigmentosum patient suffers thus causing changes to the bases themselves, such as the methylation of guanine to O6MeG, which base-pairs with thymine, or the UV-induced creation of thymine dimers.

Single Stranded Breaks : deals in a nick in the sugar-phosphate backbone of one strand.  This is caused by peroxides, Cu++ ion, oxygen radicals, or ionizing radiation.

Double stranded Breaks: this is where both strand backbones are broken.  This is typically caused by ionizing radiation. this is the most lethal of all