Xeroderma pigmentosum (XP) is heterogeneous group of diseases associated with defects in DNA repair, inherited in an autosomal recessive manner. Exposure of DNA to UV radiation produces photoproducts based on multiple nucleic acids, which serve as a substrate for DNA excision repair (NER). Mutations in the NER pathway genes result in impaired DNA repair and it associated with variety of clinical syndromes, which include xeroderma pigmentosa, Cockaynes syndrome, and trichothiodystrophy. Some forms of the disease are accompanied by damage to the central nervous system. In recent years, precise molecular anomalies responsible for complementation patterns have been identified. All the patients with this disease have photosensitivity, an increased risk of skin cancer and melanoma, but there are number of differences between them. Considering the rare frequency of occurring this disease throughout the world, this article presents our own clinical observation of an 8-year-old patient with xeroderma pigmentosa. The first change on the girls skin appeared at the age of 2 months after insolation, in the form of hyperemia of the skin and blisters, later on multiple pigmented rashes of varying intensity appeared. Upon admission to the clinic, the girl had small dark brown spots and depigmented scars on her face and open areas of the body. Sequencing revealed the NGS variant in the hemizygous state in the XPA gene. Early diagnosis and preventive measures can dramatically improve and prolong the lives of patients. Considering the genetic heterogeneity, molecular diagnosis is an important step in the diagnosis and prognosis of the disease.
