OBJECTIVE: To explore the genetic pathogenesis of X-linked agammaglobulinemia in two patients for clinical diagnosis and family counseling. METHODS: Data was collected from the patients' family including clinical information, blood immunoglobulin level, as well as classification and subgrouping of B lymphocytes. Gene mutations were screened by whole exome sequencing (WES) through next-generation sequencing (NGS), the result was verified with Sanger sequencing. RESULTS: A BTK c.1627T>C (p.Ser543Pro) variant was found in the pedigree. The phenotype and variant have co-segregated in the pedigree. The variant was not found in population database. The variant has affected in the kinase domain which contained no benign variants and is harmful as predicted through bioinformatic analysis. CONCLUSION BTK c.1627T>C (p.Ser543Pro) is a pathogenic variant contributing to X-linked agammaglobulinemia in this pedigree. Above finding has provided reproduction guidance for this family.
Agammaglobulinaemia Tyrosine Kinase/genetics* ; Agammaglobulinemia/genetics* ; DNA Mutational Analysis ; Genetic Diseases, X-Linked ; Humans ; Mutation ; Pedigree

RNA helicases are involved in almost every aspect of RNA, from transcription to RNA decay. DExD/H-box helicases comprise the largest SF2 helicase superfamily, which are characterized by two conserved RecA-like domains. In recent years, an increasing number of unexpected functions of these proteins have been discovered. They play important roles not only in innate immune response but also in diseases like cancers and chronic hepatitis C. In this review, we summarize the recent literatures on one member of the SF2 superfamily, the DEAD-box protein DDX41. After bacterial or viral infection, DNA or cyclic-di-GMP is released to cells. After phosphorylation of Tyr414 by BTK kinase, DDX41 will act as a sensor to recognize the invaders, followed by induction of type I interferons (IFN). After the immune response, DDX41 is degraded by the E3 ligase TRIM21, using Lys9 and Lys115 of DDX41 as the ubiquitination sites. Besides the roles in innate immunity, DDX41 is also related to diseases. An increasing number of both inherited and acquired mutations in DDX41 gene are identified from myelodysplastic syndrome and/or acute myeloid leukemia (MDS/AML) patients. The review focuses on DDX41, as well as its homolog Abstrakt in Drosophila, which is important for survival at all stages throughout the life cycle of the fly.
Agammaglobulinaemia Tyrosine Kinase ; Animals ; Bacterial Infections ; genetics ; immunology ; Cyclic GMP ; analogs & derivatives ; genetics ; immunology ; DEAD-box RNA Helicases ; genetics ; immunology ; Drosophila Proteins ; genetics ; immunology ; Drosophila melanogaster ; Humans ; Leukemia, Myeloid, Acute ; genetics ; immunology ; Mutation ; Myelodysplastic Syndromes ; genetics ; immunology ; Nuclear Proteins ; genetics ; immunology ; Protein-Tyrosine Kinases ; genetics ; immunology ; Virus Diseases ; genetics ; immunology

This research investigated the clinical features of immunodeficiency disease and the features of the mutation of its pathogenic genes. All 7 patients were boys aged 5 months to 4 years and 6 months and had a history of recurrent respiratory infection and pneumonia, low levels of IgM and IgG, and abnormal absolute values or percentages of lymphocyte subsets. High-throughput sequencing showed c.1684C>T mutations in the BTK gene in patient 1 and IVS8+2T>C splice site mutations in the BTK gene in patient 2. Both of these mutations came from their mothers. Patients 3, 4, and 5 had mutations in the IL2RG gene, i.e., c.298C>T, IVS3-2A>G, and c.164T>A, among which c.164T>A mutations had not been reported. Patient 6 had c.204C>G mutations in the RAG2 gene. Patient 7 had complex heterozygous mutations of c.913C>T and c.824G>A in the RAG2 gene, which came from his father and mother, respectively. Patients with immunodeficiency disease have abnormal immunological indices, and high-throughput sequencing helps to make a definite diagnosis.
Agammaglobulinaemia Tyrosine Kinase ; Agammaglobulinemia ; genetics ; Child, Preschool ; Computational Biology ; DNA-Binding Proteins ; genetics ; Genetic Diseases, X-Linked ; genetics ; High-Throughput Nucleotide Sequencing ; Humans ; Immunologic Deficiency Syndromes ; genetics ; therapy ; Infant ; Interleukin Receptor Common gamma Subunit ; genetics ; Male ; Mutation ; Nuclear Proteins ; genetics ; Protein-Tyrosine Kinases ; genetics