Kira R, Ihara K, Takada H, Gondo K, Hara T
Department of Pediatrics, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Hum Genet. 1998 Jun;102(6):605-10. doi: 10.1007/s004390050749.
Deficiency of the ninth component of human complement (C9) is the most common complement deficiency in Japan but is rare in other countries. We studied the molecular basis of C9 deficiency in four Japanese C9-deficient patients who had suffered from meningococcal meningitis. Direct sequencing of amplified C9 cDNA and DNA revealed a nonsense substitution (CGA-->TGA) at codon 95 in exon 4 in the four C9-deficient individuals. An allele-specific polymerase chain reaction system designed to detect exclusively only one of the normal and mutant alleles indicated that all the four patients were homozygous for the mutation in exon 4 and that the parents of patient 2 were heterozygous. The common mutation at codon 95 in exon 4 might be responsible for most Japanese C9 deficiency.
人类补体第九成分（C9）缺乏症在日本是最常见的补体缺乏症，但在其他国家则较为罕见。我们研究了4名患有脑膜炎球菌性脑膜炎的日本C9缺乏症患者C9缺乏的分子基础。对扩增的C9 cDNA和DNA进行直接测序，发现在4名C9缺乏个体的外显子4的第95密码子处存在无义替代（CGA→TGA）。专门设计用于仅检测正常和突变等位基因之一的等位基因特异性聚合酶链反应系统表明，所有4名患者在外显子4中的突变均为纯合子，患者2的父母为杂合子。外显子4中第95密码子处的常见突变可能是大多数日本C9缺乏症的原因。
