Complement Component 8a (C8a)

In a 24-year-old black woman with 3 episodes of disseminated gonococcal infection, Petersen et al. found severe deficiency of C8. Michelotti et al. isolated overlapping genomic clones and used them to decipher the organization of the human C8A gene. The gene contains at least 11 exons and spans approximately 70 kb of DNA. C8A genomic organization was found to be remarkably similar to that of C6, C8B, and C9. Although the C8A and C8B loci were previously reported to be less than 2.5-kb apart, Michelotti et al. obtained results using exon-specific probes, indicating that the loci are not as closely linked as initially believed. Komatsu et al. and Komatsu et al. described hereditary C8-alpha-gamma deficiency in the rabbit where it was associated with dwarfism, small thymus, small litter size, and low survival rate.