• 1
    Petersen BH, Lee TJ, Snyderman R, Brooks GF. Neisseria meningitidis and Neisseria gonorrhoea bacteraemia associated with C6, C7 or C8 deficiency. Ann Intern Med 1979; 90:91720.
  • 2
    Ross SC, Densen P. Complement deficiency status and infection: epidemiology, pathogenesis and consequences of Neisserial and other infections in an immune deficiency. Medicine 1984; 63:24373.
  • 3
    Figueroa JE, Densen P. Infectious diseases associated with complement deficiencies. Clin Microbiol 1991; 4:35995.
  • 4
    Ram S, Lewis LL, Rice PA. Infections of people with complement deficiencies and patients who have undergone splenectomy. Clin Microbiol Rev 2010; 23:74080.
  • 5
    Orren A, Potter PC, Cooper R, du Toit E. Deficiency of the sixth component of complement and susceptibility to Neisseria meningitidis infections. Studies in ten families and five isolated cases. Immunology 1987; 62:24953.
  • 6
    Orren A, Würzner R, Potter PC et al. Properties of a low molecular weight complement component C6 found in human subjects with subtotal C6 deficiency. Immunology 1992; 75:106.
  • 7
    Würzner R, Orren A, Potter P et al. Functionally active complement proteins C6 and C7 detected in C6- and C7-deficient individuals. Clin Exp Immunol 1991; 83:4307.
  • 8
    Potter PC, Frasch CE, van der Sande WJM, Cooper RC, Patel Y, Orren A. Prophylaxis against Neisseria meningitidis infections and antibody responses in patients with deficiency of the sixth component of complement. J Infect Dis 1990; 161:9327.
  • 9
    Hobart MJ, Fernie BA, Fijen KAPM, Orren A. The molecular bases of C6 deficiency in the Western Cape, South Africa. Hum Genet 1998; 103:50612.
  • 10
    Parham KL, Roberts A, Thomas A et al. Prevalence of mutations leading to complete C6 deficiency (C6Q0) in the Western Cape, South Africa and detection of novel mutations leading to C6Q0 in an Irish family. Mol Immunol 2007; 44:275660.
  • 11
    Orren A, Warren RE, Potter PC, Jones AM, Lachmann PJ, Poolman JT. Antibodies to meningococcal class 1 outer membrane proteins in South African complement deficient and complement sufficient subjects. Infect Immun 1992; 60:451015.
  • 12
    Morgan BP. Complement haemolytic activity. In: Morgan BP, ed. Complement methods and protocols. Totowa, NJ: Humana Press, 2000:617.
  • 13
    Statistics South Africa. Census 2001, Pretoria. Published 2003. Available at: (accessed 1 January 2011).
  • 14
    Den Dunnen JT, Antonarakis SE. Mutation nomenclature extensions and suggestions to describe complex mutations: a discussion. Hum Mutat 2000; 15:712.
  • 15
    Antonarakis SE. Recommendations for a nomenclature system for human gene mutations. Nomenclature Working Group. Hum Mutat 1998; 11:13.
  • 16
    Newcombe RG, Altman DG. Proportions and their differences. In: Altman DG, Machin D, Bryant TN et al., eds. Statistics with confidence, 2nd edn. London: BMJ Books, 2000; 45:56.
  • 17
    Wilson EB. Probable inference, the law of succession, and statistical inference. J Am Stat Assoc 1927; 22:20913.
  • 18
    R Development Core Team. r: a language and environment for statistical computing. 2011. Available at: (accessed 1 January 2011).
  • 19
    Coulson GB, von Gottberg A, du Plessis M, Smith AM, de Gouvia L, Klugman KP. Meningococcal disease in South Africa, 1999–2002. Emerg Infect Dis 2007; 13:2738.
  • 20
    Pérez-Caballero D, García-Laorden I, Cortés G, Wessels MR, de Córdoba SR, Albertí S. Interaction between complement regulators and Streptococcus pyogenes: binding of C4b-binding protein and factor H/factor H-like protein 1 to M18 strains involves two different cell surface molecules. J Immunol 2004; 173:6899904.
  • 21
    Davie AM. The ‘singles’ method for segregation analysis under incomplete ascertainment. Ann Hum Genet 1979; 42:50712.
  • 22
    Quintana-Murci L, Harmant C, Quach H et al. Strong maternal Khoisan contribution to the South African coloured population: a case of gender-biased admixture. Am J Hum Genet 2010; 86:61120.