Molecular diagnostics of primary immunodeficiencies in Sverdlovsk region

The article presents the results of the work performed by the laboratory of molecular diagnostics at the Medical Center “Health Care of Mother and Child” for the diagnosis of primary immunodeficiency in Sverdlovsk region over 5 years. The laboratory was organized in 2009 to verify the diagnosis of monogenic hereditary diseases included in the Neonatal Screening Program in the Russian Federation, e.g., phenylketonuria, cystic fibrosis, classical galactosemia. Over time, the range of diagnosed nosologies expanded, and since 2014, the laboratory has included in studies of a new group of disorders, i.e., congenital errors of immunity. Every year the Regional Registry of patients with primary immunodeficiencies (PIDs) replenished by 20 to 70 persons, thus comprising 15 to 43% of the entire Russian Registry for these conditions. As of 03/01/2020, the registry of patients with a clinical diagnosis of “primary immunodeficiency” consisted of 526 people, more than half of them (275) being children under 18 years of age. According to the expert calculations, the frequency of detected PID cases in the Sverdlovsk region is 1:10 480 inhabitants, which indicates not only high level of the existing clinical immunology service, but also the high expected frequency of PID in the region. Until 2014, verification of the “primary immunodeficiency” diagnosis in the patients from Sverdlovsk region was traditionally carried out in Moscow clinics (Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow Research Centre for Medical Genetics). Over 6 years of cooperation between regional immunological service with the medical genetic center, 47 children received molecular genetic confirmation of the diagnosis of congenital immunity errors at the laboratory of Regional Medical Center “Health Care of Mother and Child”. The authors present the data of Regional Registry of patients, classified into nosological forms of immune-dependent pathology and provide a detailed description of diagnostic procedures for the patients with various PIDs. A deletion of chromosome 22 (Di Giorgi syndrome) was found in 43 people, mutations in the Btk gene (X-linked agammaglobulinemia) were revealed in 7 patients and 6 members of their families, Nijmegen syndrome was confirmed in 1 child, a familial case of ADA-deficiency, difficult for diagnostics, was decided. The results of the study encourage the authors for further expansion of the spectrum of detectable disorders diagnosis, and give a hope that development of regional laboratories at this level may improve the diagnostic algorithm for PID diagnostic procedures in Russia, i.e., from prenatal and neonatal screening to the development of gene therapy for certain forms of immune-dependent disorders.

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