Newborn screening in North Ossetia in 2023–2024

Mass screening of newborns for 36 hereditary diseases in the Russian Federation will enable the reduction of childhood disability and mortality from hereditary disorders, as well as the identification of all-Russian and regional population-genetic features of the screened disorders. The study aimed to assess the results of newborn screening (NBS), including expanded newborn screening (ENBS), in the Republic of North Ossetia-Alania obtained between January 1, 2023, and December 31, 2024, as well as to study clinical and population-genetic characteristics of the diseases screened in the region. In phase I of assessment, biochemical testing, tandem mass spectrometry, and DNA diagnostics were performed, and the TREС/KREС levels were determined in 14,994 newborns. In 355 cases (2.36%), positive values were revealed. In phase II, the necessary laboratory and subsequent confirmatory DNA diagnostics were carried out in 324 cases (91.2%): repeated analysis by MS/MS and DNA diagnostics (for hereditary metabolic diseases), immunophenotyping (for primary immunodeficiency states). During the 2-year study, a total of 37 diagnoses were established, which accounted for 0.25% of all children screened in phase I and clearly indicated the program's success and effectiveness. We managed to verify the specific spectrum of mutations characteristic of phenylketonuria (PKU) and medium-chain fatty acid acyl-CoA dehydrogenase deficiency (MCADD). The frequency of the disorder assessed within the framework of newborn screening was determined. The frequency of all PKU forms was 1 : 1153 newborns, and the frequency of MCADD was 1 : 789 newborns surveyed. All children are listed as sick in the medical genetic consultation of the Republic of North Ossetia-Alania; they receive treatment in accordance with the clinical guidelines.