Primary immune deficiencies are usually attributed to genetic defects and, therefore, frequently referred to as inborn errors of immunity (IEI). We subjected the genomic DNA of 333 patients with ...clinical signs of IEI to next generation sequencing (NGS) analysis of 344 immunity‐related genes and, in some instances, additional genetic techniques. Genetic causes of the disease were identified in 69/333 (21%) of subjects, including 11/18 (61%) of children with syndrome‐associated IEIs, 45/202 (22%) of nonsyndromic patients with Jeffrey Modell Foundation (JMF) warning signs, 9/56 (16%) of subjects with periodic fever, 3/30 (10%) of cases of autoimmune cytopenia, 1/21 (5%) of patients with unusually severe infections and 0/6 (0%) of individuals with isolated elevation of IgE level. There were unusual clinical observations: twins with severe immunodeficiency carried a de novo CHARGE syndrome‐associated SEMA3E c.2108C>T (p.S703L) allele; however, they lacked clinical features of CHARGE syndrome. Additionally, there were genetically proven instances of Netherton syndrome, Х‐linked agammaglobulinemia, severe combined immune deficiency (SCID), IPEX and APECED syndromes, among others. Some patients carried recurrent pathogenic alleles, such as AIRE c.769C>T (p.R257*), NBN c.657del5, DCLRE1C c.103C>G (p.H35D), NLRP12 c.1054C>T (p.R352C) and c.910C>T (p.H304Y). NGS is a powerful tool for high‐throughput examination of patients with malfunction of immunity.
