Identification of two novel mutations in patients with X-linked primary immunodeficiencies

Primary immunodeficiency diseases (PID) are a heterogeneous group of inherited disorders with defects in one or more component of the immune system. In this study, we analyzed gene mutations in four X-linked PID pedigrees, which include one X- linked agammaglobulinemia (XLA) pedigree, one X-linked chronic granulomatous disease (XCGD) pedigree, and two X-linked Hyper IgM syndrome (XHIGM) pedigrees. Sequence analysis of the BTK gene revealed a novel mutation (c.1802_1803delinsGCC, p.Phe601CysfsX3) which results in the developmental arrest of B cells in the bone marrow. Sequence analysis of the CYBB gene revealed a recurrent frameshift mutation (c.1313_1314delinsT) in exon 10, which generates a premature stop codon (p.Lys438IlefsX63). One novel frameshift mutation (c.114delG, p.Ser39GlnfsX14) and one recurrent missense mutation (c.499G>C, p.Gly167Arg) were found in the CD40LG gene and cause defective T cell functioning. In conclusion, our study identified two novel mutations on the BTK and CD40LG genes in Chinese patients and established accurate and simple genetic diagnostic methods for three X-linked PID.