Nijmegen syndrome is a rare monogenic pathology with an autosomal recessive type of inheritance. The disease is manifested by congenital developmental anomalies and microcephaly, primary immunodeficiency, frequent recurrent viral and bacterial infections, retardation in physical and neuropsychic development. In the medical literature, 150 cases of the syndrome are described; pathology occurs more often among the Slavic population. Nijmegen syndrome belongs to a group of diseases with chromosomal instability. The pathogenetic feature of the syndrome is congenital immunodeficiency of the humoral (B-lymphocytes) and cellular (T-lymphocytes) components. According to statistics, 40 % of children with Nijmegen syndrome are diagnosed with malignant neoplasms. lymphoid tissue is more often affected (non-Hodgkin’s B and T-cell lymphomas, acute lymphoblastic leukemia), and the development of solid neoplasia is also possible. To diagnose Nijmegen syndrome, in addition to assessing the patient clinical status, it is necessary to conduct an extended immunological examination with the determination of immunoglobulins A, M, G and molecular genetic studies.

The article presents a clinical case of diagnosis and treatment of Nijmegen syndrome in childhood.