Özet:

Introduction. Ataxia-telangiectasia (A-T) or Louis-Bar’s syndrome and Nijmegen breakage syndrome (NBS) belong to primary immunodeficiencies associated with impaired DNA repair, because of the damage to genes involved in the repair system. The peculiarity of these orphan diseases is that the onset and development of clinical manifestations depend on the severity of genome instability, the rate of accumulation of mutations determining the severity of the course for each individual patient. Cases presentation. The clinical cases of the syndrome A-T in a 4-year-old child and NBS in an 8-year-old child are presented in this article. The dynamics of clinical symptoms and their evolution were analyzed. The authors identified common clinical and immunological features of A-T and NBS in the examined children. The features of clinical cases were compared with data from the scientific literature. Conclusions. The complexities of the A-T and NBS diagnosis, due to the peculiarities of the course in different patients and the variability of the onset of the first clinical manifestations, are highlighted. The analyzed clinical cases will contribute to better physicians’ awareness and vigilance regarding the early diagnosis of primary immunodeficiency, that will prevent serious complications. Keywords: ataxia-telangiectasia, Nijmegen breakage syndrome, DNA repair, primary immunodeficiency.

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