Sakamoto M, Kanegane H, Fujii H, Tsukada S, Miyawaki T, Shinomiya N
Second Department of Pediatrics, Toho University School of Medicine, Tokyo, Japan.
Am J Med Genet. 2001 Mar 15;99(3):234-7. doi: 10.1002/1096-8628(2001)9999:9999<::aid-ajmg1159>3.0.co;2-m.
X-linked agammaglobulinemia (XLA) is an immunodeficiency caused by abnormalities in tyrosine kinase (BTK), and is characterized by a deficiency of peripheral blood B cells. We studied cytoplasmic expression of BTK protein and analyzed the BTK gene (BTK) in peripheral blood mononuclear cells from two siblings with XLA and additional family members. Cytoplasmic expression of BTK protein in monocytes was not detected in either patient with XLA. A single base deletion (C563) in BTK-exon 6, which encodes the TH domain, was identified in both XLA patients. However, normal cytoplasmic expression of BTK protein in monocytes was detected in their mother without any BTK mutation. These results strongly suggest germinal mosaicism in the mother.
X连锁无丙种球蛋白血症（XLA）是一种由酪氨酸激酶（BTK）异常引起的免疫缺陷病，其特征是外周血B细胞缺乏。我们研究了BTK蛋白的细胞质表达，并分析了两名患有XLA的兄弟姐妹及其他家庭成员外周血单个核细胞中的BTK基因（BTK）。两名XLA患者的单核细胞中均未检测到BTK蛋白的细胞质表达。在两名XLA患者中均发现BTK外显子6（编码TH结构域）存在单个碱基缺失（C563）。然而，在其母亲的单核细胞中检测到BTK蛋白的正常细胞质表达，且其母亲没有任何BTK突变。这些结果强烈提示母亲存在生殖腺嵌合体现象。
