title: A novel Bruton's tyrosine kinase gene (BTK) missense mutation in a Chinese family with X-linked agammaglobulinemia.
abstract: BACKGROUND
  X-linked agammaglobulinemia (XLA) is a rare inherited disease characterized by recurrent bacterial infections, a paucity or absence of peripheral lymphoid tissue, an absence of circulating B cells, and marked depression of serum IgG, IgA, and IgM. Germline mutation of the BTK gene has been identified as a cause of XLA. These mutations cause defects in early B cell development.
  
  
  METHODS
  In this study, we report a variant form of XLA with partial B cell function that results from a missense mutation (c.1117C > G) in exon 13 of the BTK gene. A genetic analysis of the family revealed an affected male sibling with a c.1117C > G mutation. He was observed with low level of serum immunoglobulin and CD19+ B cell and received the IVIG replacement therapy regularly in follow up. Four female carriers were found.
  
  
  CONCLUSIONS
  BTK mutation analysis is necessary in the diagnosis of XLA and may be used for subsequent genetic counseling, carrier detection and prenatal diagnosis.
authors.forename: Bixia
authors.initials: B
authors.lastname: Zheng
authors.forename: Yayuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Rheumatology and Immunology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China. yuhaiguo73@126.com.
authors.forename: Haiguo
authors.initials: H
authors.lastname: Yu
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000361:Agammaglobulinemia / Q000235:genetics* / Q000628:therapy; D002648:Child; D002681:China; D005260:Female; D040181:Genetic Diseases, X-Linked / Q000235:genetics* / Q000628:therapy; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D011505:Protein-Tyrosine Kinases / Q000235:genetics*
chemical_list: D016756:Immunoglobulins, Intravenous; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human