Young Cuban Patients with a Clinical and biochemical Diagnosis of Xeroderma Pigmentosum

Foundation: skin cancer is a complication of xeroderma pigmentosum; early diagnosis is important. The alkaline comet assay with ultraviolet C radiation and the western blot assay are useful for diagnosis. Objective: to evaluate the capacity of deoxyribonucleic acid repair against ultraviolet C radiation and to determine the expression of eta polymerase in Cuban patients. Methods: a case series study, including four patients with a presumptive diagnosis of xeroderma pigmentosum, established by a multidisciplinary national medical commission. The capacity of deoxyribonucleic acid repair against ultraviolet C radiation was evaluated by the alkaline comet assay and the expression of eta polymerase was determined by the western blot assay. Peripheral blood lymphocytes were used. Results: in two patients, the alkaline comet assay showed a competent repair phenotype (62.3% and 139% respectively). The other two patients had deficient repair, suggesting the presence of one of the classic forms of the disease. In all four patients, expression of eta polymerase was detected by western blot; in the two who had normal repair, the protein band was weak, indicating that they might have the variant of the disease. Conclusions: the evaluation of the deoxyribonucleic acid repair phenotype with ultraviolet C radiation and of the expression of eta polymerase in peripheral blood lymphocytes contributes to a precise clinical diagnosis of xeroderma pigmentosum in Cuban patients.