PRIMARY COMBINED IMMUNODEFICIENCY WITH CERNUNNOS PROTEIN DEFICIENCY: CLINICAL CASES AND BIBLIOGRAPHICAL REVIEW

One of the well-known groups of primary immunodeficiency conditions includes primary immunodeficiencies with impaired DNA repair. Primary immunodeficiencies with impaired DNA repair include immunodeficiency with Cernunnos protein deficiency. Pathogenic biallelic genetic variants in the NHEJ1 gene lead to the development of this immunodeficiency. The Cernunnos protein is involved in the processes of non-homologous DNA repair and V(D)J recombination of T- and B-lymphocyte receptors. In the clinical picture of patients with Cernunnos protein deficiency, the leading manifestations are the following: infectious complications within the framework of combined immunodeficiency, cytopenia, autoimmune complications. Like most primary immunodeficiencies with impaired DNA repair, immunodeficiencies with a defect in the NHEJ1 gene are characterized by a predisposition to the development of malignant neoplasms. The only curative treatment for patients with primary immunodeficiency conditions associated with Cernunnos protein deficiency is allogeneic hematopoietic stem cell transplantation.