Zheng Bixia, Zhang Yayuan, Jin Yu, Yu Haiguo
Department of Rheumatology and Immunology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China.
BMC Pediatr. 2014 Oct 15;14:265. doi: 10.1186/1471-2431-14-265.
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.
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.
BTK mutation analysis is necessary in the diagnosis of XLA and may be used for subsequent genetic counseling, carrier detection and prenatal diagnosis.
X连锁无丙种球蛋白血症（XLA）是一种罕见的遗传性疾病，其特征为反复细菌感染、外周淋巴组织稀少或缺失、循环B细胞缺乏以及血清IgG、IgA和IgM显著降低。BTK基因的种系突变已被确定为XLA的病因。这些突变导致早期B细胞发育缺陷。
在本研究中，我们报告了一种具有部分B细胞功能的XLA变异形式，其由BTK基因第13外显子中的错义突变（c.1117C＞G）引起。对该家族的基因分析发现一名受影响的男性同胞存在c.1117C＞G突变。观察到他血清免疫球蛋白和CD19+B细胞水平较低，并在随访中定期接受静脉注射免疫球蛋白替代治疗。发现了四名女性携带者。
BTK突变分析对于XLA的诊断是必要的，并且可用于后续的遗传咨询、携带者检测和产前诊断。
