Molecular bases for inherited human complement component C6 deficiency in two unrelated individuals

Hiroaki Nishizaka, Takahiko Horiuchi, Zeng Bian Zhu, Yasuo Fukumori, Kohei Nagasawa, Kenshi Hayashi, Richard Krumdieck, C. Glenn Cobbs, Masanori Higuchi, Shin'ichiro Yasunaga, Yoshiyuki Niho, John E. Volanakis

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


Deficiency of the sixth component of complement (C6D) is frequently associated with recurrent neisserial infections, especially meningitis caused by Neisseria meningitidis. We here report the molecular bases of C6D in two unrelated subjects, one African American (case 1) and the other Japanese (case 2). Screening all 17 exons of the C6 gene and their boundaries by exon- specific PCR/single strand conformation polymorphism demonstrated aberrant single stranded DNA fragments in exon 12 of case 1 and exon 2 of case 2. Nucleotide sequencing of the amplified DNA fragments revealed a homozygous single-base deletion (G1936) in exon 12 of case 1 and a heterozygous single base deletion (C291/C292/C293/C294) in exon 2 of case 2. Both mutations resulted in frame shifts and premature termination of the C6 polypeptide. Sequence-specific oligonucleotide probe hybridization and direct sequencing of exon 12 amplified from genomic DNA further supported the homozygosity of the mutation in case 1. Case 2 is apparently compound heterozygote, but the putative mutation in the other allele of the C6 gene remains unknown. Both case 1 and case 2 were homozygous for the C6A allotype. These data indicate that at least three distinct mutational events can cause C6D, single nucleotide deletions in exons 2 and 12, and a mutation as yet unidentified. Thus, similar to other complement protein deficiencies, the pathogenesis of C6D appears to be heterogeneous.

Original languageEnglish
Pages (from-to)2309-2315
Number of pages7
JournalJournal of Immunology
Issue number6
Publication statusPublished - Mar 15 1996

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


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